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Patrick1
10-05-2007, 06:39 PM
After checking Brian's lightfastness test in the Oil Painting Forum, which includes Alizarin Crimson, here's mine. It's W&N Artists' PR83, indoors in a south-facing window, and mounted at approx. a 45ļ angle to better catch the sunlight. The right half is the control sample kept in a dark box. At the bottom is a tint with Titanium White. This is from April 2007 to Oct. 2007, though I'm not stopping any time soon, this is fun, I'm gonna keep it going.

By comparison, W&N Winton Cadmium Red Medium shows no visible fading, but I should've done a Quinacridone instead for comparison.

Einion
10-06-2007, 05:30 AM
Super, thanks for posting this Patrick http://www.wetcanvas.com/Community/images/20-Aug-2003/3842-thumbsup.gif

This is from April 2007 to Oct. 2007, though I'm not stopping any time soon, this is fun, I'm gonna keep it going.
Hey, it'll be no fun when it's all white! :D

Einion

Patrick1
10-06-2007, 03:23 PM
Yeah, it's getting close to the point where I wonder whether I should finish this torture test - if you let the samples fade too much, it can become difficult to compare the pigments to one another because there's not much color left. But I'm only doing two pigments right now so what the heck.

I should note that lower down, the paint is intentionally applied extremely thin to get quick results; I thinned with artists' thinner. But then again, I did the same for the Cadmium Red which so far is fine. The tint is applied thickly (perhaps a more realistic application for oils & acrylics), and it isn't doing too hot either.

Brian Firth
10-08-2007, 09:34 AM
Good to see your results. I am starting to think Alizarin Crimson isn't lightfast! :) It looks like the 45 degree angle helped accelerate the tests even more. It is really apparent that Alizarin crimson is really fugitive in glazes, even worse than in tints with white.

Einion
10-08-2007, 12:31 PM
Good to see your results. I am starting to think Alizarin Crimson isn't lightfast! :)
:lol:

Einion

Patrick1
10-08-2007, 01:04 PM
Here's Gamblin's Alizarin Permanent vs. the real thing:

http://www.gamblincolors.com/artists.grade.oils/reds/img/alizarins.jpg

The description:

Alizarin Permanent: Cool, slightly bluish red with smoky glaze. Robert Gamblin has mixed lightfast pigments to form a true replacement for Alizarin Crimson. Slightly more intense in tint, but excellent match in masstone and transparency.

Pigment: Quinacridone red b, perylene red, ultramarine blue (PV 19, PR 149, PB 29)
Vehicle: Alkali refined linseed oil
Lightfastness I, Series 3, TRANSPARENT,

Even if the Permanent is slightly more intense in tints (I assume it means slightly higher chroma when tinted to the exact same value), are there any good reason(s) any more to use real Alizarin? (And I'm not asking rhetorically, I truly want to know if there are any good reasons).

Einion
10-08-2007, 02:28 PM
Even if the Permanent is slightly more intense in tints (I assume it means slightly higher chroma when tinted to the exact same value), are there any good reason(s) any more to use real Alizarin? (And I'm not asking rhetorically, I truly want to know if there are any good reasons).
Unfortunately the answer to that is going to be subjective; anyone like us is going to say no (I think that anyway of course, regardless of there being a 'suitable replacement' :) ) but people in the other camp will generally continue to disagree from what I've seen - just look at the professional watercolourists that turn a blind eye to the issue.

Anyway, back to the Gamblin paint, I'd like to take the opportunity to repeat Richard Schmid's comment, "as far as I can tell, it is a perfect match". Now I've read one or two members' opinions that disagree but hey, not like there are any guarantees in this world and we all know pigments vary (Ali Crimsons are by no means a single colour).

But all this is really beside the point: one does not need an equivalent colour as a replacement. The thousands of painters that don't use a crimson paint, but do work of a similar type to those who do, show this with absolute clarity. PR177, PV19 of one type or another, PR264, PR N/A and of course PR122 could all take the rough position in the palette between red and violet; then it's just a matter of adapting mixing routines/procedures, which really doesn't take that much effort.

Einion

Patrick1
10-08-2007, 03:35 PM
And then there's the issue of tinting strength; if the replacement is higher in tinting strength, as long as it's not excessive, it's not difficult to simply change the mixing proportions a bit (just like you would anyways when switching from student grade to artists' grade).

BTW, those artists that didn't find Gamblin's Alizarin replacement to be close enough, in what way did they say it wasn't close enough? I don't see a difference in the photo I linked to.

Einion
10-09-2007, 06:22 AM
BTW, those artists that didn't find Gamblin's Alizarin replacement to be close enough, in what way did they say it wasn't close enough? I don't see a difference in the photo I linked to.
I had a huge problem searching for prior mentions of it with any negative comments about the colour specifically but here are two (from the same thread):

In spite of the fact that Schmid claims the Gamblin is a dead on match, I have not found it to be so.... The Gamblin and my Gamblin immitation mixes (from the same pigments Gamblin uses) came closest in value, but none matched the vibrancy and purity of the color alizarin*. Those that came closest in the vibrancy department lacked the dark value, though some were close.
What I noticed(my eyes only) is that the Williamsburg 'Permanent Crimson' retains the warmth, not as blue as the Gamblin, more like true Alizarin C.

I'm sure I've read others (since I don't think I saw the thread the above quotes are from!) but it'll have to remain hearsay if I can't locate them.

Einion

*In relation to the bit you highlighted, slightly more intense in tint, I guess this must relate to tinting strength rather than chroma? I also read the wording to mean as you did, supporting the argument for clear, unequivocal language in paint literature. As far as I'm concerned intensity is a synonym for chroma or saturation or brilliance; if they didn't mean that - i.e. if they did mean tinting strength - why didn't they just say so?

Richard Saylor
10-10-2007, 03:04 AM
Genuine aliz. crimson is very yesterday. It is rapidly disappearing from commercial watercolor and gouache. If one wants to flirt with danger, there are much more exciting fugitive colors with which to play, such as Opera (an aptly named color, as volatile and dangerous as Carmen herself); as well as less suggestively named colors, such as WN's Primary Red Gouache(a fluorescent red, the color-equivalent of a potent central nervous system stimulant).

JamieWG
10-10-2007, 12:17 PM
Oh, this is so very unfair. I want to play too, and my samples aren't showing anything yet! They've been in the window for 7 months. I think I'll have to move them to an upstairs window, and tilt them too. I was up at the Golden headquarters a couple of months ago, and they had all their tests tilted to face the sun.

In my window are:
Winsor Newton Artist Alizarin
Grumbacher Alizarin
Utrecht Alizarin
Winsor Newton Artist Permanent Alizarin
Gamblin Permanent Alizarin
My own mix using the same pigments as Gamblin
Two other mixes of mine for permanent alizarin matches

I have found the permanent alizarins on the market to have equal chroma straight out of the tube, but less when mixed. The Gamblin perment alizarin is not as clean in mixes as the genuine. The Winsor Newton Permanent Alizarin turns more reddish in tints than the genuine. For me, either is close enough. I'm a little concerned about Marc Hanson's tests for the Gamblin mix, and so I'm not trusting perylene PR149 at all anymore, until I can see for myself that it's holding up in sunlight.

Jamie

Patrick1
10-10-2007, 12:40 PM
Jamie, are your samples facing south (more or less) ? Yes, angling will help a bit. But perhaps the most important thing is making sure that the thinnest parts of the sample are drawn down VERY thin, which requires using thinner.

JamieWG
10-10-2007, 03:07 PM
Jamie, are your samples facing south (more or less) ? Yes, angling will help a bit. But perhaps the most important thing is making sure that the thinnest parts of the sample are drawn down VERY thin, which requires using thinner.

Patrick, they're in a south facing window, but it's on the first floor, with a tree outside. LOL....Works fine in winter, but I probably lost quite a bit of sunlight in the spring and summer. I think it will fare better in an upstairs south facing window on the other side of the house. I was trying to avoid plastering lightfastness tests against the picture window in the living room. Maybe my husband won't notice. ;)

I did not use thinner for the tests. I brushed squares of the samples three ways: thick undiluted, very thin undiluted, and cut half with white, medium application thickness. When I do more, I will take your advice and use thinner.

Jamie

Brian Firth
10-10-2007, 05:06 PM
You don't need to use thinner for the tests. It is more important to have tints with white. The purpose is to replicate how you would use the paints in a painting, and unless you are doing "stain" type paintings with extremely thinned paints, then the results wouldn't be relevant to normal oil paintings.

Patrick1
10-10-2007, 06:57 PM
You could do the entire test using white to lighten all the way to the lightest gradation, but as you can see you'll be waiting much longer for the results; look at the tint on the right and find the same value of wash above it, and then compare the amount in fading in the tint vs. the wash. The light wash makes it easier to compare one pigment to another because it makes the differences much easier to see. Next time I'll also do my tint in full gradation.

JamieWG
10-11-2007, 06:32 AM
Thanks, Brian and Patrick. I'll start with moving the samples today. I want to get more up into the window in the next week or so---especially perylene by itself, plus some acrylics and gouache. I'll take your comments into consideration when preparing my next samples.

Jamie

Brian Firth
10-12-2007, 10:39 AM
In my tests of W&N Finity acrylic Perylene Red PR149 did not fade, but darkened moderately after a year of sunlight exposure. My sample of W&N Perylene Maroon PR179 W&N Artists Watercolor also darkened slightly. I believe all perylene pigments darken when exposed to sunlight for long periods of time. They did not show darkening until the very last few months of the tests, much longer after alizarin crimson started to fade, so in my opinion they are still lightfast. I have attached the two scans of the test samples below. I applied the acrylic in a thin wash in a watercolor type application.

Daniel_OB
03-30-2008, 08:44 PM
Alizarin Crimson, PR83, made by Michael Hardings and Old Holland, is lightfast pigment. PR83 must not be set into tint. PR177 is permanent but no so as tint too. The differnce is that PR83 is more sensitive on tint. It also must not be "diluted" with medium. Less pigment concentration lower permance. So if one neet to tint or dilute it, it is much better to do glazing instead, for and PR83 and PR177 are very transparent pigments.
And one think more: PR83 and PR177 to use effectively with permanence must be used with Copal (I think Groves 50% concentration is the best). Copal extend permanence of all pigments.
Again: no thining, no tinting, use Copal, and PR83/177 are at all permant pigments. Also note that exposure to direct Sunlight accelerate fading/darkening around 100 times, compared to normal environment for the same.

Daniel OB


Alizarin Crimson, PR83, is not permanent if we make it impermanent

Patrick1
03-31-2008, 05:20 AM
Alizarin Crimson, PR83, made by Michael Hardings and Old Holland, is lightfast pigment.
...PR83 must not be set into tint. ...It also must not be "diluted" with medium. ...So if one neet to tint or dilute it, it is much better to do glazing instead... PR83 and PR177 to use effectively with permanence must be used with Copal... Again: no thining, no tinting, use Copal...

If, after all this, you still consider Alizarin Crimson lightfast, what would be an example of a non-lightrfast pigment? :lol:

Einion
03-31-2008, 05:27 AM
Alizarin Crimson, PR83, made by Michael Hardings and Old Holland, is lightfast pigment.
No, it's not Daniel.

Lightfastness is not a rating of a pigment when used only in certain ways, it is a measure of a pigment's total performance. What makes this so important in this case is that many painters want to use a crimson paint in exactly the ways that it's most at risk - in tints with white and in light glazes. In either case it can eventually bleach to nothing (literally vanishing).

One can choose to have a pigment on the palette that can be used safely only in certain ways, nobody's stopping you. But I think that it's much better to build the entire palette from paints that can all be used any way you like, with complete assurance of reliability; you're free to disagree Daniel, they're your paintings.

PR177 is permanent but no so as tint too.
That's overstating it, performance for this pigment varies. Some versions are a lot more lightfast than others, hence the need to conduct one's own lightfastness tests if this is a personal concern.

And one think more: PR83 and PR177 to use effectively with permanence must be used with Copal (I think Groves 50% concentration is the best). Copal extend permanence of all pigments.
Evidence please?

Also note that exposure to direct Sunlight accelerate fading/darkening around 100 times...
Let's make up some numbers shall we? :rolleyes:

Einion

Daniel_OB
03-31-2008, 07:02 AM
"Evidence please?"
Einion, here are examples: Artrist's Assistant, Dr. Carlyle.

Alizarin is expencive pigment. And so through history, as many of other pigments too, is fakid (for evidence see the same book as above). Paint makers (and Colorman too), in general, do not make paints, they make monney and it is their primary interest. It is why I once said it is a must for anyone presenting his test here to remain us on the maker and approximate age of the tube. I personaly beleive only to two colormen, two I mentioned above, and so if I see paint test of some other makes I just do not loose time around it. I think the nicer example how think can run differnt way is example of Vermilion.
And to test pigment on direct Sunlight is to me a little strange, even I do it. Real painting will nearly never be exposed to such condition. I am not Chemist but I know that even and short exposure to Sunlight (say several hous) can change "some" think in the painting. On several places it is mentioned in Dr. Carlyle book (see above). I also know how it influence Copal and Amber too.
Not sure and I just beleive, that "real" Mader and Alizarin should not fade exposed to normal lite for one painting, and (well do not know name this moment) some English autors said "age enhance them", which means a little get darker.

I cannot afford to test paints at normal indoor light, so I always try to find historical data. In principle I do not beleive a lot in accelerated tests. Sometimes it is the only means and cannot this moment get where I found that direct Sunlight accelerate test around 100 times, as a general guide only. What I can say is that I do not beleive in just anything I see and am very carefull in selecting sources.

And for evidence about Copal. It is not just for Copal but Amber too. They lock-up pigment, when used in proper way, completely changing its permanence (extend). It comes also from Dr Carlyle and her study of historical evidences, not accelerated tests.

So again, there are use of Alizarin where it can show as not good enough, and also there are ways of its use to make it "permanent". I think it can be said for many other pigments that are even considered extremely permanent. Example can be chemical reaction within the film when pigment is not used in right way. Chemical engineers knows it much better.

Daniel_OB
03-31-2008, 07:22 AM
Patric
An example of non-lightfast pigment is Holbein Vermilion. There are no way, known to me, to save it from significient value change.

Einion
03-31-2008, 02:54 PM
Daniel, could you quote any actual passages that state what you claimed above (at least give page references for anyone that might also own it)? Even with specific references within it, isn't that book a summary of 18th- and 19th-century manuals on oil painting? If the information in it is merely a summation of the older material it can hardly be considered evidence. If that is the case we can't trust the info any more than we can trust de Mayerne or Cennini or Maroger by themselves, without supportive data... just look at all the fallacies in Maroger's conclusions that we've now found.

And to test pigment on direct Sunlight is to me a little strange, even I do it.
Light fades pigments. The more light the faster the results. That's basically it in a nutshell; it's not a lot more complex than that.

And for evidence about Copal. It is not just for Copal but Amber too. They lock-up pigment, when used in proper way, completely changing its permanence (extend).
Permanence and lightfastness are not necessarily the same thing, although obviously the second is an aspect of the first.

In the case of historical pigments, where a number were chemically unstable, the idea of added resins - within or on top of paint layers - makes some sense (although the discolouration is an obvious downside) but we're talking about stability with exposure to light.

I personaly beleive only to two colormen, two I mentioned above...
You can continue to believe what you want on this front but as I think I've mentioned to you in the past: OH have one of the worst reputations with regard to their choices of pigment historically, not the best. Not to put too fine a point on it but they have also been caught, more than once, in outright lies in their literature. I would strongly recommend that be borne in mind.

Einion

JamieWG
03-31-2008, 04:47 PM
I just pulled down my tests of Winsor Newton Artist Alizarin, Grumbacher Alizarin, and Utrecht Alizarin. They went into the window on 3/3/07. They have faded just a tiny bit so far (painted rather thickly), with the Grumbacher showing the most fading of the three.

Jamie

Daniel_OB
04-01-2008, 10:55 AM
Daniel, could you quote any actual passages that state what you claimed above (at least give page references for anyone that might also own it)?

Artist's Assistant, Carlyle (price around $240)
One ref is here:
page 228, left column, bottom, just above the Fig.
There are more similar things throughout the book
It is about "handling semi-permanent pigment"

--------------------
"Even with specific references within it, isn't that book a summary of 18th- and 19th-century manuals on oil painting?"
Yes, it is about the matter...
----------------
"If the information in it is merely a summation of the older material it can hardly be considered evidence. If that is the case we can't trust the info any more than we can trust de Mayerne or Cennini or Maroger by themselves, without supportive data... just look at all the fallacies in Maroger's conclusions that we've now found."

1. The source for the book is material from her Doctoral disertation. So it is not just repetation what is already said. It comments on it.

2. Many of other, World round, conservators scientist took part in the book (consultation, advices, proof reading,...), some sources from Yale literature is consulted, and so on.

3. She is extremely experieced and knowlegeable, head in Canadian Conservation Institute, then TATE gallery London,... Google will help to trace something.

4. She do not, as said, just repeat whatever is said already. She had free choice what to include into the book, and if something, by her knowledge, do not fits into what she is sure is correct, I assume she skipped or used as "not to do" and gave own comment on the matter, and why. So the book is collection of "good" things for oil painters. Why she will just repeat what is wrong, and to say it?
--------------
To compare to Cennini and what he wrote: if 99% is wrong in that book and 1% is correct should we discard that 1%? But one should be master to spot that 1%. So it is the core, and because of that I consider the book is one of the most usefull on the market today, and probably a long ahead.

JamieWG
04-01-2008, 12:58 PM
It seems to me that "semi-permanent" = non archival.

Jamie

Daniel_OB
04-03-2008, 10:42 AM
Using Alizarin Crimson thined or tinted is bad idea. It is alrady tested hundreds times. No one passed. Some says it is idiotic to recomend such think with Alizarin. Alizarin Crimson is not fugitive it is extremely fugitive, as Einion said so many times.
If your test shows no hard fading your paint is not Alizarin it is something else (e.g. some mix). Tesitng A. Crimson again and again is losing time.
If you want to thin or tint it you drop pigment concentration. More tint faster will fade. In this case it is better idea to use Benzimida pigment (I think PR175) e.g. from Old Holland (schwenningen crimson ... you find out exact name). To use Alizarin it must be straight from the tube and locked-up with Copal or Umber. No other way.
The same is valid for PR177, even it is somehow better than PR83.

Daniel_OB
04-03-2008, 10:53 AM
Einion
"... OH have one of the worst reputations with regard to their choices of pigment historically, not the best..."
Can you please meke it more clear

"... Not to put too fine a point on it but they have also been caught, more than once, in outright lies in their literature. I would strongly recommend that be borne in mind."
I would like to have an example. Some salesman or new guy from OH, not so familiar with pigments, might be is involved. I would like to explore it.
I am a guy that do not beleive to anyone and is extremely selective. But I cannot reject just anyone. If I do from who I will buy paints or pigment...

Einion
04-03-2008, 04:36 PM
Can you please meke it more clear
They often choose an example of a pigment that has poor lightfastness, among a number being tested (not infrequently the poorest (http://www.handprint.com/HP/WCL/waterc.html#PR177)). Even though the Handprint data (for this and for the next point) is for their watercolours it's likely the very same pigments are in their oil paint, which will perform better, but still it highlights that the pigments chosen could easily be of higher quality; given the high pricetag why aren't they?

They sometimes offer the least-brilliant example of a pigment among a number being compared - this is not just a nuance thing, very noticeably dullest.

Before I was online I had never heard a good word about OH's products because of the shoddy reputation their watercolours had so it came as some surprise to me that they had this steller rep among certain oil painters.

I would like to have an example. Some salesman or new guy from OH, not so familiar with pigments, might be is involved.
I think you missed the last part Daniel: ...outright lies in their literature.

I highlighted one of their current classics to you before, here (http://www.wetcanvas.com/forums/showthread.php?p=6479532#post6479532) (where the PR177 example was previously given). That wording, "ASTM category 1 and 2", in addition to simply being too generic to actually be helpful, is provably an outright fabrication.

In the past it's well know (check old threads if you want) that they claimed their oil line was all 'completely lightfast', despite it having PR83 in it. They used to have four or five colours where this was an ingredient - remember these paints would have had to be equally lightfast to, say, Burnt Umber, Mars Black, Venetian Red, Yellow Ochre! This is of course nonsense. Possibly in part because of us here at WC! highlighting that the claim simply could not be accurate the range was revamped a short while later.

One of their brochures used to say that they made paint for Rubens I think it was, despite him being dead before their 'founding date' (24 years apart!) That date has another problem - it's supposedly the date that this company was founded, when in fact in 1981 here is what the company claimed in an introductory letter about the brand:
Old Holland Oil Colors is one of the last small and top quality oil color houses in the world, located in the Hague, Holland. The owner's grandfather was Willem Roelofs, one of the forerunners of the dutch impressionists, known as the "Hague School". His work hangs in many musea.

Willem's son Albert made a name as a portrait painter - painting himself into a small fortune. This allowed him to spend time searching for better color recipes as he was not happy with what was available then. He made careful investigation of the recipes of the seventeenth century Dutch masters, keeping those that had proven their superiority, and adding some more recently invented colors like cobalt blue. He created a workshop where he made the best materials possible for his own use. Then, artist-friends began to ask him for samples. Soon that same workshop became a small factory, now known as Old Holland Oil Colors Manufactory (or in French "Couleurs de la Haye"). It is still the same workshop. Albert's son is the president of the company now. The recipes and methods of preparation are still the same.

Ever read their leaflet where they suggest you check the heft of a tube of their paint v. a competitor's example of the same colour? Okay, but just above this they made a point of the fact that they still use lead tubes because they're so much better, their competitors having gone to aluminium... now, last time I checked lead is a hell of a lot heavier than aluminium! The underlying point they're trying to make is valid but there's no getting away from how misleading they're being.

Last point I'm going to make, and I'm not sure if they still stick to this claim, but they did at one point say that their oil was all windmill-pressed, when the supplier of the oil told one member of WC! directly that this was not the case and that in fact only a portion of it is still pressed using wind power.

There is more but this is enough to show that it's not an isolated thing, but part of a pattern.

Einion

Paint_Tube
04-03-2008, 04:52 PM
An example of non-lightfast pigment is Holbein Vermilion. There are no way, known to me, to save it from significient value change.
That's highly anomalous; I have used Holbein Vermilion and have experienced no problems in over a year. Why would it change? Holbein Vermilion is made with PR108, Cadmium Scarlet! I for one have never met a PR108 I didn't like.
Are you referring to the Vermilion HUE?

EDIT: My apologies, I had it in my head that you were talking about the watercolor line when you were obviously referring to the oils. Sorry, brain lapse. I recall that they still use mercury sulfide for the line of oils, so you're pretty much right on the money about that.

As far as Alizarin Crimson, I wouldn't be surprised if it's completely rendered obsolete in the near future. We're in the age of the perylenes and the quinacridones, after all. Why keep appealing to tradition when time and time again it's been demonstrated that PR83 is not lightfast?
I'm thoroughly skeptical of any claim that one brand makes a lightfast PR83 paint, especially if it comes from Old Holland. (Eesh)

-J-

gunzorro
04-03-2008, 09:20 PM
I've conducted casual experiments and seen AC fade, and so has Brian Firth. But we should be clear that although AC is not the most lightfast pigment in oils, it is not truly fugitive or non-lightfast in most indoor exposure without direct sunlight. Most manufacturers list AC as "fair" lightfastness, or III out of four levels.

I don't see manufacturers dropping AC until artists stop requesting it. It is a lovely color and hard to resist. I've found substitutes, but nothing I would consider an exact match that is completely lightfast.

My test results did concern me though, and I have been reducing my stocks of various AC. Some are more lightfast than others, but I am getting rid of almost all the OH paints that have PR83 as a component (keeping one tube for reference). I am keeping an older supply of WN from the 70s which exhibited the best lightfastness. Gone are the more recent WN, Vasari and Harding.

Daniel_OB
04-04-2008, 09:11 PM
Gunzorro did you try Old Holland Scheveningen purple brown,
Pigment: Benzimidazilone (PR175)

This one is transparent and should make all mixes similar to Aliz. Cr. Also it is very permanent pigment.

Smokin
04-06-2008, 02:03 AM
But we should be clear that although AC is not the most lightfast pigment in oils, it is not truly fugitive or non-lightfast in most indoor exposure without direct sunlight.

Thats the point thats unfortunatly getting lost. The way a lightfast test strongly influnces people's judgment or opinon on pigments on a whole I find somwhat comical.

PR83 is the synthetic creation of the original Madder pigment, N_somthing(9?). They are identical in structure and in every way except a slight difference in lightfastness in original madder's favor. These 2 pigments are usually called Alizerine Crimson and have been used for centuries with both failures and sucesses documented. Something to note, there are painting that are CENTURIES old that still sport a very beautiful crimson color. Some of these newer, more lightfast pigments can't claim the same thing yet.

Lightfastness, ...... its a test to apply a grade to a paint based on how well it performs when its blasted with certain types light in certain conditions. I wish I could find specific info on how ASTM conducts these tests, but that unfortunatly costs a pretty penny to find out. Esentially though its placed in machines to blast it with different types of light and then they check how far the value changed. The blue cotton test was the common lightfast test used prior to ASTM's and in this test AC performed well and was considered lightfast. This is relevant, because time could bring us new ways to test pigments lightfastness that might alter our perception of the permanence of other pigments.

I have a few problems with alot of these homemade lightfast tests being performed. The first thing that needs to be considered is the type of medium is being used. For example, Brians water color test has nothing to do with how PR83 performs in guache, oil, or acrylics. Im not suggesting that it was implied it was, just saying it doesnt dispite what similar results one may have.

The history of PR83 & Original Madder (I'll call OG83) is they have always been poor tinters. Semi permanent in that in some situations it was fugative, and in other it was permantent. If PR83 or OG83 were mixed with most minerals or metalic pigments (like lead,ochres, siennas), alizerine would be fugative and known to fade. If used alone or with some select pigments such as burnt oxides or alone it would be perfectly permanent. Frans hals and Rembrants are 2 artists who were known to use alizerine correctly, Sir Joshua Reynold was one who used alizerine crimson incorectly which resulted in bleached faces and hands, almost ghost like faces. His students however painted the clothing and other elements in his portrait (an acceptible practice of the time) and used alizerine correctly.

I dont know if PR83 was chemically altered in any significant way as to make any of this history now moot, but since I couldnt find any info, Ill assume its still relevant today. BUt that brings me back to lightfastness tests where Ive seen many mix PR83 with lead white. Sunlight or not that will bleach alizerine, I bet the sun speeds things along personally. Most of the tests Ive seen where pure PR83 is applied, there is lil to no change in value. The steps after that when white is added, I personally ignore.

Chasing direct sunlight is also not a practical way to test permanence either. Its certainly a factor worth considering for sure, but still, its only one factor of many. If I were talking to an outdoor muralist, I would say pick somthing other than PR83. But for the rest, any direct sunlight is going to bleach a painting. Red ylw, blue, white, its all going to get bleached somewhat. Some whites will brighten and lighten significantly in sunlight, thats technically a poor lightfast pigmnent no?

Lightfastness has very little to do with overall permanence of a pigment. Again, its certainly somthing to consider, but just not the only thing. For example, in the past there were forms of lead paint that where made that were perfectly lightfast, but because of a poor ratio of carbonate and other lead junk, it would desintegrat and chalk off over time. Zinc as we all know should never be used pure, it may be lightfast, but itll shatter on you if you dont know how to use it. I personaly pick pigments that I can find a history to because I think that only with time can we understand pigments. I was mocked in another thread because I was "defending" a pigment with a history of failures, but the history of falures shows me how not to use the pigment, and how I can use it with confidence & permancy. Why I will not use some of these more "permanent alizerines" is because there is no history of thier use. It may turn out over time that these are a perfect replacment for alizerine or superior, but it worth metioning that people at one point held the same confidence in pr83 as many do for these newer pigments. Pigments dont fade to oblivion just because of light, there are many other factors. It may turn out that some of these newer pigments are going to be museums nightmare, who knows?

Einion
04-06-2008, 09:01 AM
Thats the point thats unfortunatly getting lost.
It's not getting lost. Quite the opposite in fact; this thread has very thoroughly covered both perspectives, it's just that people on either side are very entrenched in their views.

Something to note, there are painting that are CENTURIES old that still sport a very beautiful crimson color.
Achem, don't forget retouching.

Some of these newer, more lightfast pigments can't claim the same thing yet.
While that's true they can claim vastly-superior test results. Since the tests are a reflection of real-world fading - otherwise there would be no point to them (and they wouldn't be relied upon by industry) - they do tell us what will fare better.

And in case anyone is unaware of this there are any number of decades-long exposure tests going on around the world, confirming whether accelerated testing of pigment performance is reflected in daylight exposure.

The blue cotton test was the common lightfast test used prior to ASTM's and in this test AC performed well and was considered lightfast.
Firstly, the Blue-Wool Scale is a means to comparatively measure fading with direct comparison to something.

Second, it was not a testing procedure per se. See more on this page (http://www.handprint.com/HP/WCL/pigmt6.html) from the Handprint site.

And thirdly, could you provide the data that supports the claim that PR83 "performed well"? In masstone, in an oil binder perhaps? But we're not concerned with just the masstone or with this pigment in oil only. If you are that's fine, however other people's standards are different.

Sunlight or not that will bleach alizerine, I bet the sun speeds things along personally.
Of course it speed things along, that's why you do direct exposure tests so you don't have to wait 10-30 years for a result!

Most of the tests Ive seen where pure PR83 is applied, there is lil to no change in value.
Value is not the only factor.

The steps after that when white is added, I personally ignore.
Your opinion is duly noted, but that is part of how a pigment is normally used (in watercolour, thinner glazes).

If I were talking to an outdoor muralist, I would say pick somthing other than PR83. But for the rest, any direct sunlight is going to bleach a painting. Red ylw, blue, white, its all going to get bleached somewhat.
There are any number of pigments that can withstand decades of exposure to light without fading...

Lightfastness has very little to do with overall permanence of a pigment.
In the modern context it is essentially the only factor worth noting. Very few pigments manufactured today are chemically unstable or chemically reactive and certainly none that are would be suitable for use in artists' materials.

Why I will not use some of these more "permanent alizerines" is because there is no history of thier use.
So I presume you don't use phthalo blues and greens, pyrroles, quinacridones?

What about French Ultramarine and the cadmiums, their history long enough for you to use them with confidence?

It may turn out over time that these are a perfect replacment for alizerine or superior, but it worth metioning that people at one point held the same confidence in pr83 as many do for these newer pigments.
From the page linked to above:
In 1907, a committee of artists and manufacturers met in Germany to set industry lightfastness standards, and adopted alizarin crimson (PR83) as a minimum lightfastness standard.

Pigments dont fade to oblivion just because of light, there are many other factors.
Light is the only significant factor for almost all pigments we're concerned with.

Einion

Smokin
04-06-2008, 11:32 AM
_"Retouching"
Achem, are you seriously trying to pretend that that the alizerine we see in all the Franz Hals and Rembrandt works are because or retouching? :lol: Do those retouchers have something against all of Sir Joshua's works?

While that's true they can claim vastly-superior test results. Since the tests are a reflection of real-world fading - otherwise there would be no point to them (and they wouldn't be relied upon by industry) - they do tell us what will fare better.

They do no such thing. The lightfastness test, tests fading with respect to light (Specific lighting to be exact), has NOTHING to do with how well a pigment will fare in the long run against other elements or conditions. The industry selling the pigments are useing lightfastness ratings as a marketing tools, and the industry using pigments understand there are other concerns other than just lightfastness to understand.

"Blue wool test is not a test"
Its the test the industry used on thier pigments. There is a reason why people felt alizerine was completely lightfast, and it wasnt because of a just gut feeling.
http://www.kremer-pigmente.de/shopint/index.php?cat=01030101&lang=ENG&product=23610

Of course it speed things along, that's why you do direct exposure tests so you don't have to wait 10-30 years for a result!

Any bleaching effect caused by another pigmnent , accelerated or not under direct sunlight conditions, still has NOTHING to do with lightfastness. If I took bleach crystals (porb dont exsist), and mulled them with the best lightfast pigment and saw it fade away in the sun, is that pigment all of a sudden, no longer lightfast?

Value is not the only factor.
Value, colors, hue, ect

In the modern context it is essentially the only factor worth noting. Very few pigments manufactured today are chemically unstable or chemically reactive and certainly none that are would be suitable for use in artists' materials.

Thats a pretty bold assumption, especially with the number of new companies out and about. If one does not learn from history, one is doomed to repeat it. History showed us that the falure to pigemtns were many times due to poor processing and poor manufacting which is alot less common today. But there are many other situations where environment conditions, bad reactions, or just simply an unexpected deteriation just happenes after a certain point in time.

So I presume you don't use phthalo blues and greens, pyrroles, quinacridones?
What about French Ultramarine and the cadmiums, their history long enough for you to use them with confidence?

I dont use pyroles or quidacerones or pthalos, though I can find a wonderful history, tests, and case studies on phthalo if it where a color I suddenly became intrerested in. Same goes it Franch ultramarine, and cads,(which i do use) they may not be from the renisance era, but I have over a century or more of collected info tests sucesses and falures for these pigments. Oh and there were sucesses and falures for all the above btw.

Light is the only significant factor for almost all pigments we're concerned with.

Thats the point, for you it obviously is, for me its only one factor of many.

Daniel_OB
04-06-2008, 03:39 PM
Smokin
I would agree with you that PR83/177 can be made permanent, but not PR83 plus plus plus... No tint, no diluting...
But the problem is, as Einion try to tell us (she actually do not need to tell us it, so if one like it use it), how it will perform within the mix. As known to me, we do not have replacement for Aliz.Cr. I tried and spent a lot of money and time, but no any luck. I can use it as tube for something (e.g. roses, clothes, ...) but how about the skin. Many painters, me too, will not accept just any formula from internet. We use Aliz.Cr. as a mix with e.g. Vermilion (and other colors too). We cannot use Aliz.Cr. alone for figure painting. Might it is time for me to run into mix investigations. This moment I use only M.Harding PR83 and OldHolland PR177 (they call it Burgundy Wine Red). I will also try PR175 from OldHolland. And look what I am doing. I cannot test paint. When I figure out that it is good or wrong, no one make it any more. And what I will do until the test is over?

Patrick1
04-07-2008, 03:50 PM
Update: Alizarin Crimson and Cadmium Red Medium one year after the test started. The Cadmium Red still shows no noticeable change.

Daniel_OB
04-07-2008, 08:23 PM
Partic
Can you please explain what are exatly tests conditions (say direct Sunlight,..., South California, ...)
What brand is it?
Is it PR83 or PR177.
What are two spots at the bottom?

Patrick1
04-07-2008, 09:05 PM
Hi Daniel...I answer those questions in the first post in this thread. I'll add: it's direct sunlight, and I live in Ottawa (Southern California - I wish!).

AAL
04-10-2008, 06:33 AM
There are some references to the handprint site
http://www.handprint.com/HP/WCL/water.html

It is well worth a visit if you haven't been there yet. Another question though - What is the relative lightfastness of a fugitive color in watercolour, oil and acrylic and has this been thoroughly tested.

Tony

gunzorro
04-11-2008, 01:54 AM
Daniel -- Yes, I have OH Schev. Purple Brown, but it is purple-brown. Lovely, but not a replacement for Alizarin. PR177 is the closest I've found to Alizarin for blending, but slightly lighter and brighter in masstone. PR177, while not 100% lightfast, is an improvement on genuine Alizarin.

Daniel_OB
04-11-2008, 11:41 AM
Thanks gunzorro
Yes, PR177 is very simillar to PR83. But the problem with PR177 is the same as with PR83, even as you said less, but the problem is still around, and it is: PR177 is not good when tinted (will fade too). Both should be used as mass tone only, otherwise bad supprise.
To make very white underlayer for alizarin to get higher value after glazing with tube PR177, will not work too. Paints with white underlayer fade faster...

Einion
04-11-2008, 02:27 PM
Since this thread is still going...

_"Retouching"
Achem, are you seriously trying to pretend that that the alizerine we see in all the Franz Hals and Rembrandt works are because or retouching?
Are you trying to pretend that no paintings are retouched? ;) Remember, I didn't say any example of an intense red in an old painting would be due to retouching, but some are.

As far as Hals and Rembrandt specifically - if you could point to individual works where it's known that madder lakes are present and that they're original please do, I'd like to see them.

I have seen many Hals pieces in the flesh and in the main they featured a subdued colouring (not unlike Caravaggio's work). As you may know, many reds/crimsons were combinations of glazes over a red underpainting (similar to how Ultramarine was used in a lot of cases). So even with the fading of the lake some of the original intent would remain; very often that is exactly what we're left with unless the glazing was re-applied during retouching at some point ('superficial retouching').

"Blue wool test is not a test"
What I said was:
[the Blue-Wool Scale is] not a testing procedure per se....

There is a reason why people felt alizerine was completely lightfast, and it wasnt because of a just gut feeling.
Even if this were the case what they believed historically isn't relevant here. It's well documented why the synthetic version was widely adopted once it became available, despite the differences in colour between it and the real madder lakes.

http://www.kremer-pigmente.de/shopint/index.php?cat=01030101&lang=ENG&product=23610
Yes, that has been posted before. I still await an explanation. There is no way that "Thinned: 7" is right for that if PG7 (http://www.kremer-pigmente.de/shopint/index.php?cat=01030101&lang=ENG&product=23000) and PB15:1 (http://www.kremer-pigmente.de/shopint/index.php?cat=01030101&lang=ENG&product=23050) are accurate.

This is the very type of thing that should make one question the anomalous results, not cause us to suddenly question all the other tests. PR83 is ASTM III in oils let's not forget, q.v. the first post of this very thread + the update, Brian Firth's example here (http://www.wetcanvas.com/forums/showthread.php?t=448871), the Wilcox guide, Hilary Page (http://www.hilarypage.com/Hilary%20Page's%20Guide%20to%20Watercolor%20Paints%20-%20Update%20'00_files/8AlizCrim.jpg ), Handprint (http://www.handprint.com/HP/WCL/IMG/LF/LFR83.jpg) and countless other tests, plus the observation in this post (http://www.wetcanvas.com/forums/showthread.php?p=898615&highlight=alizarin+does+fade#post898615) by member Leopoldo. They cannot all be 'wrong' or however one wants to refer to it.

Any bleaching effect caused by another pigmnent , accelerated or not under direct sunlight conditions, still has NOTHING to do with lightfastness.
That's not quite what the white is doing; it's merely an avenue to showing up the weakness that is already present (just as a glaze test does...) Referring back to the point I made in post #20, fading in tints does have everything to do with functional lightfastness. And honestly, let's not beat around the bush here: this is not some bizarre test that doesn't seem to have any bearing on the real world, it's merely a recreation of a perfectly normal, everyday use a pigment might be put to!

There's really no point in arguing against this since there are dozens of pigments that when mixed into equivalent tints, or used in light glazes, don't fade; ergo the fugitive nature of those that do is unequivocal.

If this:

http://www.wetcanvas.com/Community/images/11-Apr-2008/3842-Crimson_Fade_Illus.JPG

is good enough for you fair enough, that's your call. But if you want to suggest that this is not the case then present evidence, don't just make the claim.

As far as the causes of fading are concerned, for the bulk of pigments used in artists' materials today, in typical usage, light is the major player. If you wish to delve into this issue further then please start a new thread on lightfastness/permanence factors, testing etc.

Einion

Einion
04-11-2008, 02:36 PM
Update: Alizarin Crimson and Cadmium Red Medium one year after the test started.
Coming along nicely, thanks for the update.


Yes, PR177 is very simillar to PR83. But the problem with PR177 is the same as with PR83, even as you said less, but the problem is still around, and it is: PR177 is not good when tinted (will fade too).
Can fade is not the same as will fade. (http://www.wetcanvas.com/forums/showthread.php?p=6673252#post6673252) Typically this pigment is lightfast enough (in oils certainly) for artistic use.

Einion

nit-wit
04-11-2008, 04:35 PM
Patrick,

It's a shame that you didn't make a systematic photographic record in constant lighting of this project. Or did you? I think that it would have made a lovely stop frame animated film. I'd have liked to watch the fading on youtube.

The question that springs to mind is: would a collector refrain from buying a painting where there is a use of AC?

Andrew

Einion
04-12-2008, 03:55 AM
The question that springs to mind is: would a collector refrain from buying a painting where there is a use of AC?
How would they know? I don't think many artists make a point of mentioning specific colours are used (and it would seem counter-productive in this case!)

Einion

Brian Firth
04-12-2008, 07:48 AM
Thanks gunzorro
Yes, PR177 is very simillar to PR83. But the problem with PR177 is the same as with PR83, even as you said less, but the problem is still around, and it is: PR177 is not good when tinted (will fade too). Both should be used as mass tone only, otherwise bad supprise.
To make very white underlayer for alizarin to get higher value after glazing with tube PR177, will not work too. Paints with white underlayer fade faster...


Again, in my tests Winsor and Newton PR177 proved to be be absolutely lightfast, even in tints, while alizarin crimson faded in both tints and undertone in the same time (1 year of South facing sunlight). Winsor and Newton PR177 is lightfast and is lightfast in tints.

nit-wit
04-15-2008, 04:57 AM
How would they know? I don't think many artists make a point of mentioning specific colours are used (and it would seem counter-productive in this case!)

Einion

True, but I'd know if AC had been used, you would certainly know if AC had been used, and everyone else who's contributed to this post would know. But AC is such a useful colour it's a shame not to use it.

There's quite a lot of paintings that have 'altered' over time but it doesn't appear to affect their quality?? This VG church for instance has definately altered. I believe the path at least has faded considerably (according to a TV programme that I once watched). But the picture hangs together still quite well.

http://www.theartistvincentvangogh.com/jpegs3-fslash-vangoghchurch-2.jpg

Andrew

Einion
04-15-2008, 06:54 AM
True, but I'd know if AC had been used, you would certainly know if AC had been used, and everyone else who's contributed to this post would know.
I'm one of the everyone else, I wouldn't know ;)

I think you're assuming the Ali Crimson would be visible as itself, which would really only be if it were used alone or maybe mixed only with white.

In most mixtures, if the paint is blended uniformly, it's impossible to know what pigments were used merely by looking with the naked eye (excluding watercolour, where pigments can give other cues than their colour alone). If one knows the age of a painting, or has prior knowledge of the palette a painter favoured, a good guess can be made but you would not be sure. One cannot even tell the difference between many single-pigment colours and a mixed equivalent, if the latter is done properly.

But AC is such a useful colour it's a shame not to use it.
Personally I think it's much more of a shame to have paintings fade within one's lifetime, especially when it can SO easily be avoided.

I believe the path at least has faded considerably (according to a TV programme that I once watched).
Yes, it used to be pink wasn't it?

Einion

nit-wit
04-15-2008, 07:31 AM
I'm one of the everyone else, I wouldn't know ;)

I think you're assuming the Ali Crimson would be visible as itself, which would really only be if it were used alone or maybe mixed only with white.


ok, point taken...


Yes, it used to be pink wasn't it?

Einion

I think you're right - maybe based on Alizarin Crimson itself? I'm not up on Van Gogh chronology but AC was introduced in 1868 (Michael Harding says so) and maybe used by VG?

Andrew

Daniel_OB
04-15-2008, 07:48 AM
Patrick1
I should note that lower down, the paint is intentionally applied extremely thin to get quick results; I thinned with artists' thinner.

What is artist's thinner?

Patrick1
04-15-2008, 08:01 PM
Daniel, it's Demco odorless solvent for oil painting.

Brian Firth
04-15-2008, 10:04 PM
I think you're right - maybe based on Alizarin Crimson itself? I'm not up on Van Gogh chronology but AC was introduced in 1868 (Michael Harding says so) and maybe used by VG?

Andrew

In his letters to Theo, Van Gogh ordered three crimson pigments: carmine, crimson lake (alizarin crimson), and geranium lake. Unfortunately, of these three pigments alizarin crimson was the most lightfast, and considerably more lightfast at that. If he had used alizarin crimson, the path would probably still be pink, although lighter than his original vision. This painting, The Church at Auvers, was painted in June 1890. In his letter to Theo dated to April 29, 1890 Van Gogh ordered only two crimson pigments, Crimson Lake and the Geranium Lake. Which indicates by this time he had stopped using the fugitive carmine. Sadly, Van Gogh was most fond of Geranium Lake, which is an incredibly fugitive eosin dye lake, and this is most likely the pigment used in the path that has completely faded away.

Smokin
04-18-2008, 06:02 AM
Are you trying to pretend that no paintings are retouched? Remember, I didn't say any example of an intense red in an old painting would be due to retouching, but some are.
As far as Hals and Rembrandt specifically - if you could point to individual works where it's known that madder lakes are present and that they're original please do, I'd like to see them.


:rolleyes: My original comment was that alizerine crimson is seen in paintings that are centuries old, yours was "achem don't forget retouching". No, I wasn't implying retouching doesn't happen by laughing at that comment.

Source: Materials for Permanent Painting by DR. Maximillion Toch, uncle of Ralph Mayer, a scientist specializing in the chemistry of paints. Ch.21 The Failure of Sir Joshua Reynold's Paintings included his observations of Rembrandt's and Hals works.

Even if this were the case what they believed historically isn't relevant here.

Historical data is relevant, The synthetic is the same as the original in chemical structure and composition though it does have a slight difference in light fastness.


Yes, that has been posted before. I still await an explanation. There is no way that "Thinned: 7" is right for that if PG7 and PB15:1 are accurate.
This is the very type of thing that should make one question the anomalous results, not cause us to suddenly question all the other tests. PR83 is ASTM III


Funny, Ive posted links that clearly showed ASTM ratings that varied from 1-4 from various manufacturers for PR83 (Not just the one from OH ). Clearly, you are dismissing any information that contradicts the one you decided as true. I personally could care less what the light fastness rating says on kremers site, I know this pigment will fade in direct sunlight, but again, I also know it's a pigment that has stood the test of time quite well so long as the painting didn't crave a tan.


I made in post #20, fading in tints does have everything to do with functional light fastness.

You said alot there I couldn't understand. I said that if you add a pigment that is known to cause a pigment to fade and become fugitive, then that has nothing to do with light fastness. I don't know what you find confusing about that.


As far as the causes of fading are concerned, for the bulk of pigments used in artists' materials today, in typical usage, light is the major player

As far as you know..... yes we established this. But by your theory, any pigment with a light fast rating of 1, should have a permanence rating of 1 as well. So why does reality tell us different?

Alizerine, Prussian blue, Ultramarine, lead white, zinc, cobalt, ochre, are a few pigments that can all fade, change color, or dissolve into oblivion in total darkness. Every good source for information on pigments understands there is no "perfect pigment", just a better understanding of how to work with it. It took a long time to figure out what and why lead white was a good solid pigment to use and how it shouldn't be used. Same with virtually every pigment we have today that we now take for granted. Based on the history, I don't assume that any new pigment on the market will stand the test of time. So far, no pigment has ever just shown up and shined without any problems.

Einion
04-18-2008, 01:48 PM
:rolleyes: My original comment was that alizerine crimson is seen in paintings that are centuries old, yours was "achem don't forget retouching". No, I wasn't implying retouching doesn't happen by laughing at that comment.
Yes, because it might be down to later retouching; since you're acknowledging here this does occur I'm not sure why it elicited laughter when I first mentioned it.

In your first and second posts you made reference to the use of madder lakes by Hals and Rembrandt - the implication being that there were examples of "a very beautiful crimson color" that you'd referred to earlier - and if there are survivals of it, at this intensity, in very old paintings how this colour is still visible is a very pertinent point to this discussion. Because this is the inevitable outcome of a madder lake exposed to light given enough time (edges protected by frame):

http://www.wetcanvas.com/Community/images/11-Apr-2008/3842-Crimson_Fade.JPG

Hence why I asked for examples where we know them to be original. I realise this is not something that we laymen can necessarily put our hands on, but it is directly relevant to the reason the point was raised and then called into question. So if there are no examples forthcoming let's drop this point (just so we're clear, that's not a request).

Source: Materials for Permanent Painting by DR. Maximillion Toch, uncle of Ralph Mayer, a scientist specializing in the chemistry of paints. Ch.21 The Failure of Sir Joshua Reynold's Paintings included his observations of Rembrandt's and Hals works.
That book was published in 1911; I'd want to read some current/more recent info in support of any factual statements. There have been strides in our understanding of certain things over the years (like the apparent lack of resins in Rembrandt works, despite the widespread belief in the early-20th century that they would be present).

Historical data is relevant...
It's certainly of interest to show what they believed to be the case at that time. But it's only relevant in support of a claim of lightfastness if it's accurate. That's all I was getting at, it wasn't a sophism just to score points. Again, also the reason I wanted examples of historical use where we know the colour is not down to later retouching.

Funny, Ive posted links that clearly showed ASTM ratings that varied from 1-4
from various manufacturers for PR83 (Not just the one from OH ).
Sorry, where?

Clearly, you are dismissing any information that contradicts the one you decided as true.
Firstly, that's the ASTM's own rating Frank, not something I "decided" on. Second, the supporting evidence that PR83 is not lightfast - in normal, everyday applications - is overwhelming, so the burden of proof therefore is on anyone that claims the opposite. To be as specific as possible: this isn't a question of lightfast enough (subjective) it's whether it's actually lightfast (objective).

Subjective - it lasts well enough FOR ME
Objective - will it fade with exposure to X amount of light

Referring back to the point I made in post #20, fading in tints does have everything to do with functional lightfastness.
You said alot there I couldn't understand.
In all seriousness, which part of this is hard to understand???
Lightfastness is not a rating of a pigment when used only in certain ways, it is a measure of a pigment's total performance. What makes this so important in this case is that many painters want to use a crimson paint in exactly the ways that it's most at risk - in tints with white and in light glazes. In either case it can eventually bleach to nothing (literally vanishing).

I said that if you add a pigment that is known to cause a pigment to fade and become fugitive, then that has nothing to do with light fastness. I don't know what you find confusing about that.
I'm confused that you find it hard to grasp that the white is "merely an avenue to showing up the weakness that is already present (just as a glaze test does...)"

I'm going to quote Brian here, since he just addressed a similar point in another thread:
Accelerated lightfast tests using the direct rays of the sun are an accepted means of determining lightfastness in artists paints by the ASTM, as well as being a method in use for over 100 years. So, yes they are valid. If you do not believe it to be, then you should take up this issue with the American Society for Testing and Materials.
This includes the issue of tints with white. We don't need to waste any more time in this thread on debating whether a pigment should or should not be tested this way or in thinner glazes, it should seem perfectly reasonable given they're a normal use for a pigment.

Einion

Einion
04-18-2008, 01:50 PM
This thread is about an issue of lightfastness, not permanence (a much wider issue with dozens of possible factors, none of which may be relevant here). If anyone wishes to delve into that issue further then start a new thread on lightfastness/permanence factors, testing etc.

Einion

Daniel_OB
04-19-2008, 03:51 PM
Einion
"That book was published in 1911; I'd want to read some current/more recent info in support of any factual statements..."

Many books made "a long ago" are by no means inferior to nowadays books. I think it is just opposite (with no many exceptions). Just one example: Janson, History of art (arond 20 yars ago made is much better than last eddition revised by some modern guys).
The one example more, out od art:
GM, DSX (Chrysl.), and Ford design departments, and their suppliers also, employ one low paid engineer and attach to him (in average) 3 students searcing google for problems solutions "engineer" deliver to them. When he "think" he got solution for the design, he make sketches and e-mail it to India where "some" guys make final design with CAD. Look where American cars are today. They are full of stripped bolts (knowing you here is evidence: "Stackpole" vane X22F pumps for GM cars). It is modern knowledge and digital days. Fortunatelly there are still guys walking to libraries. Do not overbeleive in digital guys, they are most of the time quite stupid.

Smokin
04-19-2008, 06:23 PM
Well, I was starting to respond in the typical manner that Enion likes, take this sentence respond, then take another sentence and respond. Iím not going to do that this time as I just donít think that helps anything. I took a look at my first post to this thread and I actually said all I wanted to in that one post. Why all that tit for tat responses in an unproductive way, I donít know, very few good questions or fair concerns/points came from it, rather it seemed to me it was a way to undercut the information because it conflicted with certain assumptions.

Smokin
04-19-2008, 06:25 PM
The issue of light fastness: I never suggested that alizarin would not fade in direct sunlight. I know alizarin will fade in direct sunlight, but I know it wonít fade in ambient light based on historical use of alizarin. Permanence and light fastness are two very different things and thatís always been my point, how a pigment fairs in a light fastness test will affect the overall permanence of a pigment of course. One person suggests that no alizarin seen today canít be 500 years old because the light fastness proves that the inevitable conclusion is it will disappear. That is an assumption, not evidence. Direct sunlight is very different from ambient light and frankly Iím surprised that anyone assumes this. Light doesnít get "banked". Take a damp cloth and stick it in direct sunlight, put another in a dimly lit room, one will get dark & moldy, one will get bleached and crisp. Two very different results from two very different environments. People get scared of getting skin cancer by tanning for too long, not by banking light rays to an "inevitable conclusion". Lightfastness test are designed to simulate what will happen in the long term in ambient light, but even the ASTM test clearly states that results may not reflect real world results.

As for adding white and questioning how homemade light fastness tests are done, I still havenít seen anything that makes sense or that would make anything I said moot. Adding lead white, ochre, siennas and other metallic pigments will cause alizarin to lose its permanency. Doing a lightfast test on a pigment used in a way it shouldnít be used in the first place, is not a fair way to assess a pigmentís light fastness.

Brian Firth
04-19-2008, 07:27 PM
The ASTM lightfastness rating for a specific pigment in a specific medium does not change, it is set once determined. The variations in the ratings you have noted are mistakes by manufacturers or others who have incorrectly published wrong information, they are not reflective of changes or variations made by the ASTM. THE ASTM LIGHTFASTNESS RATING DOES NOT VARY. PR83 is rated ASTM Lightfast III oil and acrylic, period.

Brian Firth
04-19-2008, 07:43 PM
[FONT=Calibri][As for adding white and questioning how homemade light fastness tests are done, I still havenít seen anything that makes sense or that would make anything I said moot. Adding lead white, ochre, siennas and other metallic pigments will cause alizarin to lose its permanency. Doing a lightfast test on a pigment used in a way it shouldnít be used in the first place, is not a fair way to assess a pigmentís light fastness.



In my tests, alizarin crimson PR83 faded the worst in an undertone scumble, without the addition of any other pigment. The tints with PW6/PW4 actually proved to hold up better than the pure pigment.

Brian Firth
04-19-2008, 07:57 PM
Also, alizarin crimson and madder were not properly laked into pigments until 1804 ( http://webexhibits.org/pigments/indiv/history/alizarin.html ). Also note from the same reference "Bleached areas of natural madder can frequently be seen on fifteenth and sixteenth century paintings."

So, the madder passages in Rembrandt's and other paintings before the early 19th century are not the same as the pigment used today. The madder would be much more a dye suspended in oil than what we are used to with modern alizarin pigment. Insect based red lakes, like Kermes Lake, cochineal, and Lac Lake, were much more prevalent before the successful laking of madder and would be the much more likely red lake used by Rembrandt and others of his time. Although, Rembrandt was known to mainly use cochineal and madder in his works. However, my point is that the madder used in old masters work is not the same as the pigment developed and used since 1804.

Smokin
04-19-2008, 09:15 PM
Brian,

You stated "THE ASTM LIGHTFASTNESS RATING DOES NOT VARY. PR83 is rated ASTM Lightfast III oil and acrylic, period." If this is true, then its still worth noting that manufacturers are very lacks about being accurate or informing their customers on permanency or lightfast ratings. If it turns out that the worst rating is the "true" astm rating, then all the manufacturers are guilty of fudging their labels a bit dishonestly.However, Ive been to ASTM's site, and I searched every which way trying to find some kind of list that states ASTM's "official lightfast ratings". I just cant find it, so if you have a link to that it would be appreciated. I don't know what to believe, are they testing themselves, are they designing the tests only, are pigments manufactured differently as to warrant a better rating,..... I don't know.

Your tests and scumbling don't surprise me, I don't look at your photos of faded alizarin and imagine that it didn't happen as you described. Still your results don't conflict with the info I have.

As for pr83 being discovered in early 1800, I am aware of that. Madder Nr9, is said to have the same chemical composition as pr83, the synthetic version of Nr9, which is why the historical data of Nr9 (madder), should be considered when evaluating pr83. Its similar to comparing the synthetic ultramarine and Lapis. They are different yes, but they share the same chemical composition which makes their characteristics, their strengths, & their weaknesses virtually identical. As for some paintings of the 16th century showing signs of fading, again, does not surprise me I did point to Sir Joshua as an example of failed application of alizarin.

http://www.artrenewal.org/asp/database/art.asp?aid=406
According to Maximillian Toch, he would paint the hands and heads on these portraits and let his students paint in the clothing. The result was that his alizarin lost its permanency because he mixed it with incompatible pigments which resulted in ghost like faces and very pale skin. His students however didn't have the same problem using alizarin. So in the same paintings , you can see both failed and successfully application of the pigment.

delicious
04-19-2008, 10:48 PM
I think Alizarin's unreliability (as an aniline pigment) is fairly well-established even if not a perfectly unanimous conclusion to all. In fact, I've heard enough about it to consider it "notorious." I don't know why a thread started based on a dramatic lightfastness test that confirms (and emphasizes) a well-known tendency fuels such a debate... I don't see what "proper use" has to do with the basic chemical weakness--maybe certain uses reduce the problem but it is still a weakness. Besides, I don't want a fussy paint when I have other choices. For me a good paint is one that takes little of my attention away from creating to think about technical challenges--my attention belongs in the painting.


If you are interested: I depend heavily on having a cool red in my palette, and am happily relying on Holbein's Carmine (PR221). I was delighted to learn that it is in a very lightfast pigment category--a "disazo condensation" is what it is called.

I have never missed the Alizarin and in fact I prefer the Carmine, and I'm glad I haven't resorted to a multiple-pigment blend either. But if anyone knows about whether the PR221 warrants concern I'd be glad to learn more.

Einion
04-20-2008, 03:26 AM
I think I need to address this publicly so I'll quote something Larry said in a previous thread:

keep the subject on topic please...comments/opinions about moderation are unnecessary;
read the user agreement, we reserve the right to sole discretion, and if comments are sarcastic, rude, crass, not likely to add to the civility of a thread...it is wholly within our perogative to remove or edit. No need to question that or assume our character traits because as volunteers we act within the office we have agreed to...
Now I hope that after reading that we're all on the same page.

I don't want to lock this thread as I would like it to remain open for posting to later on, with any updated fading results. If posts wander off the topic - as determined by myself or Larry - we will edit or remove them as we deem necessary. If you don't like this you can choose to post elsewhere; in fact we'd encourage you to do so.

Einion

Smokin
04-20-2008, 04:05 AM
I would apreciate it if you could indicate that you edited my posts and deleted content that you felt was a violation. I dont agree with that call, but what was left after the editing was not what I said and is very incomplete.

Einion
04-20-2008, 05:40 AM
I would apreciate it if you could indicate that you edited my posts and deleted content that you felt was a violation.
It is indicated, right under each post:
Reason: Violates instruction given previously
Reason: Removed off-topic portions

I dont agree with that call...
Comments/opinions about moderation are unnecessary.

...what was left after the editing was not what I said and is very incomplete.
It was either edit, in an attempt to leave portions that were relevant, or remove the posts in their entirety. The third post of that batch, which should have been posted as a new thread as per instructions (twice), was split off to here (http://www.wetcanvas.com/forums/showthread.php?t=491672).

Einion

Daniel_OB
04-21-2008, 11:09 AM
Partic1
Daniel, it's Demco odorless solvent for oil painting.

Do you mean Taltine?

Daniel_OB
04-21-2008, 11:24 AM
delicious
I have never missed the Alizarin and in fact I prefer the Carmine, and I'm glad I haven't resorted to a multiple-pigment blend either. But if anyone knows about whether the PR221 warrants concern I'd be glad to learn more.

Holbein rate and Alizarin Crimson and Carmine the same, 3 stars.

Patrick1
04-21-2008, 12:56 PM
Yup, it's Taltine.

Daniel_OB
04-24-2008, 07:31 AM
Thanks Patrick1. I tried to figure out what is Taltine actually but no luck. Is it OMS?
Can you please explain what is groung you applied paints on. It is very important, but I cannot get it from your picture.

Einion
04-24-2008, 10:22 AM
Thanks Patrick1. I tried to figure out what is Taltine actually but no luck. Is it OMS?
From the Demco site:
ODORLESS SOLVENT (Taltine):
Low odor diluent alternative to turpentine. Dries
slowly and is therefore useful in controlling alkyd and oil colours.

If you want to find out more about what it's made from then why not email the manufacturer? I'm sure they'd be willing to help.

Einion

Daniel_OB
05-08-2008, 01:52 PM
Originally Posted by Daniel_OB
Also note that exposure to direct Sunlight accelerate fading/darkening around 100 times...

Einion
"Let's make up some numbers shall we?"

Sorry I am so late on this question (did not noticed it).

Light intensity is 5 to 6 apertures difference outside/inside which is at least (not accounting reciprocity failure) 45 times difference.
Account for UV only outide/inside only 2 times (I take it and 10 times), and you got 100 times.

This does not account for gamma and x-rays, and for what we still do not know for, and also that finished painting is to great extend isolated from O2, unlike a test sample.

nit-wit
05-16-2008, 04:40 AM
Sorry a bit off the debate, but I think necessary to ask: If we assume that the original test that started this debate was scientifically sound (which it wasn't - but it does give some indication of what may happen to AC in direct sunlight (and was interesting never the less) - ACs fallibility has no doubt been proven by more rigourous methods). How many years would hanging an oil painting, containing a high end AC, in good (non-direct sunlight) conditions before marked deterioration would be seen?

In other words what does deterioration of AC under direct sunlight conditions, translate, in years, into deterioration of AC under the light conditions (non direct sunlight) of, say, a living room wall?

Many museums, most notably in my mind the Victoria & Alert Museum, protect their pictures with controlled and low lighting conditions, banishment of flash photography, atmospherically controlled conditions, and in extreme a curtain or timed lighting that may be lifted/lit to view a picture. How many years extra life would such treatment give a pigment such as AC? Sometimes though the museum is merely preserving what is left of a picture's colour.

Andrew

gunzorro
05-16-2008, 10:30 AM
I don't have a scientific basis for my opinion, just extrapolating from my tests and knowledge of how older paintings have fared. But given that a painting is not in direct sunlight, or in the path of primary indirect bounced light (like from a carpet or wall immediately adjacent), the fading should not be really noticable for a very long time.
If direct sunlight produces significant fading in 6 months, it might take 100 years to produce a similar effect on an indoor semi-exposed painting, with secondary tungsten lighting. That's not all that long in terms of archival permanence, but long enough for us and our children's children.

Einion
05-16-2008, 11:29 AM
Light intensity is 5 to 6 apertures difference outside/inside which is at least (not accounting reciprocity failure) 45 times difference.
Account for UV only outide/inside only 2 times (I take it and 10 times), and you got 100 times.
One room's illumination is, obviously, very different from another's, depending on the size, number, position and orientation of the windows in each, how that interacts with the position of the sun at different times of day and whether the sky is clear or overcast (which strongly affects the directionality of daylight). Then there are the various permutations of curtains and furnishings, as well their colour. Oh and wall colour will play a big part too.

Ergo, 100x is entirely arbitrary.

Einion

Einion
05-16-2008, 11:33 AM
If we assume that the original test that started this debate was scientifically sound (which it wasn't...
Sorry, why not?

...ACs fallibility has no doubt been proven by more rigourous methods).
Indeed it has. It's the acceptance or dismissal of that fact which most of the thread has now been (needlessly) devoted to.

In other words what does deterioration of AC under direct sunlight conditions, translate, in years, into deterioration of AC under the light conditions (non direct sunlight) of, say, a living room wall?
Depends on the livingroom wall.

The basic thing about lightfastness is that a given quanta of light, delivered over a shorter or longer time have essentially the same effect; that's the fundamental basis of lightfastness testing. The categories that the ASTM give us for acceptable lightfastness for artists (or, more pedantically, permanent work) are I and II. Even II is too low for some people with high standards, but it's pretty plain that III and IV are far below what should be considered acceptable.


I don't have a scientific basis for my opinion, just extrapolating from my tests and knowledge of how older paintings have fared. But given that a painting is not in direct sunlight, or in the path of primary indirect bounced light (like from a carpet or wall immediately adjacent), the fading should not be really noticable for a very long time.
I think you're assuming oil paint here? With watercolour (where PR83 is still very much in evidence, sadly) things are much much worse of course.

If direct sunlight produces significant fading in 6 months, it might take 100 years to produce a similar effect on an indoor semi-exposed painting, with secondary tungsten lighting. That's not all that long in terms of archival permanence, but long enough for us and our children's children.
Post #43 on page 3 has an example (post by Leopoldo I link to) that speaks to the point about 'long enough'.

Einion

nit-wit
05-16-2008, 05:05 PM
Sorry, why not?





I'm sure many discoveries have been made on a windowsill. But a windowsill isn't a controlled environment and there would be too many variables in this case to be absolutely certain that sunlight or sunlight alone was responsible for the changes seen (we just happen to understand or partially understand or think that we understand what has happened). Besides there's no proof that this was actually PR83. Or that Patrick hadn't bothered with the experiment at all and just knocked up the results to kick start a debate. OK I'm getting flippant (ridiculous even), but I do have a point.

Andrew

nit-wit
05-16-2008, 05:09 PM
But Patrick's photograph was certainly enough to get this thread going.

Andrew

Patrick1
05-16-2008, 08:08 PM
Well whatever anyone rightly or wrongly suspects might have also contributed to the disasterous fading of my Alizarin Crimson sample, the salient point is that the Cadmium Red - which was tested right next to it in the same way at the same time - showed no noticeable change (see the photo in my post #37 here).

Smokin
05-16-2008, 10:02 PM
Well whatever anyone rightly or wrongly suspects might have also contributed to the disastrous fading of my Alizarin Crimson sample, the salient point is that the Cadmium Red - which was tested right next to it in the same way at the same time - showed no noticeable change (see the photo in my post #37 here).

The salient point is that a lightfast test alone is a poor way to judge a pigment.

Cadmium while it may be more lightfast than Alizarin crimson, is also an opaque pigment, not a transparent one, which for most would not be a better choice.



The basic thing about lightfastness is that a given quanta of light, delivered over a shorter or longer time have essentially the same effect; that's the fundamental basis of lightfastness testing.

No. photochemical deterioration can't be simplified like that. Thats basically as true as saying 2+2=5 ..... its just not. I'll elaborate next week after I had a chance to check on a few resource available to me.:wave:

Mike Finn
05-17-2008, 01:20 AM
No. photochemical deterioration can't be simplified like that.

Somewhat agree. The reciprocity effect would have a bearing on the matter, as would the presence of acidic atmospheres, temperature and humidity. Still, in practice it's all we generally have and is probably enough to make a reasoned judgement.

Good discussion.

Mike Finn

Einion
05-17-2008, 06:03 AM
I'm sure many discoveries have been made on a windowsill.
Uh, penicillin, the spectrum within white light (and really stretching the example) saccharin :angel:

But a windowsill isn't a controlled environment and there would be too many variables in this case to be absolutely certain that sunlight or sunlight alone was responsible for the changes seen...
When you hear hoofbeats think horses, not zebras :)


The salient point is that a lightfast test alone is a poor way to judge a pigment.
It's a super-duper way of testing for lightfastness though.

This thread is about lightfastness which is, generally speaking, all about light.

Just a reminder: anyone who wants to discuss other elements of permanence, there was a thread split off for that express purpose, Limitations of ASTM and other ratings (http://www.wetcanvas.com/forums/showthread.php?t=491672).

Cadmium while it may be more lightfast than Alizarin crimson, is also an opaque pigment, not a transparent one, which for most would not be a better choice.
That is a specious point since we're all well aware that the same test run simultaneously will show much better results for other pigments that are transparent and are in the rough colour area of Ali Crimson. This is even in oil paint, much less in watercolour where weaknesses show up so much faster.

The basic thing about lightfastness is that a given quanta of light, delivered over a shorter or longer time have essentially the same effect; that's the fundamental basis of lightfastness testing.
No. photochemical deterioration can't be simplified like that. Thats basically as true as saying 2+2=5 ..... its just not. I'll elaborate next week after I had a chance to check on a few resource available to me.:wave:
I'm not sure if you intended that as an analogy but the basic principle is that 2+2=4 as well as 1+1+1+1.

That aside, I used the word essentially here quite deliberately; in the same spirit as the use of the word approximately in the underlined portion of the following quote:
...lightfastness tests on pigments were conducted by exposing straight-from-the-tube samples of oil paint to 600 hours of direct sunlight during the summer months of a given year. It is possible to conduct these tests using instruments that can duplicate this concentration of light (approximately equal to 100 years of exposure in a well-lighted gallery) in a much shorter time and without regard to the variables of weather conditions.

Einion

Daniel_OB
05-20-2008, 01:19 PM
Einion

"Ergo, 100x is entirely arbitrary."

And that room condition plays its own game is true too. However this indor variable does not change as close as outside variables to which painting is never exposed. As I mentioned the differnce is 5-6 apperture (this range can accomodate large differnces of indor conditions). I gave you example as an average 5.5 apperture difference. And UV influence is 2-10 times, I gave you example for 2 times. This yields 100 times differnce. However it go up to 600 times. This span can accomodate many conditions, and enyone is responsible to choose his own factor. Taking 100 times is, what I take, for heavy mix with white, lower AC quality, ....

Patric
is your sample of AC applied over ground that can draw oil out of paint, can it oxidate from behind too. These factors can completely invalidate your fading, so please explain.

Patrick1
05-23-2008, 10:16 AM
Patric
is your sample of AC applied over ground that can draw oil out of paint, can it oxidate from behind too. These factors can completely invalidate your fading, so please explain.

The samples are painted on strips of aluminum which were first primed with artists' acrylic gesso. And you still continue to suspect the Alizarin has been treated unfairly.

Why not do your own lightfastness test with Alizarin Crimson, a Cadmium Red as a known permanent reference color, and one or more Alizarin Crimson substitutes like PR 176, PR177, PR179, PR264, and some Quinacridones. And do the testing procedure in the way you think is proper. Post the results here. When the Alizarin Crimson still fades sooner than any other pigment ...no matter how you do the testing, then what?