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  #61   Report Bad Post  
Old 01-11-2011, 09:07 AM
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Einion Einion is offline
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Quote:
Originally Posted by Trond
Not so fast there. I can see where you are going here, and I think that modern pigments can reproduce any color available in the past, BUT that does not mean that everything is the same to the painter. Pigments are not just colors and values, but specific chemical compounds.
...
You can mix a cerulean blue color, but you cannot expect that mix to behave similarly with other pigments, due to differences in tinting strength and transparency.
Yep, I have addressed this numerous times in these sorts of discussions. Since even two versions of Cerulean can vary quite a bit and also not mix quite the same I don't see it as much of a problem

Quote:
Originally Posted by Trond
If you are used to genuine lead white, then switching to titanium will likely make your next painting look a bit chalky and cold.
Roger that, could well happen unless the painter takes specific steps to compensate by adjusting - mixing for the colour they want, rather than by following the same basic mixing routines they used with Lead White.

Quote:
Originally Posted by Trond
There are several reasons why old paintings look different from new ones, and one of them is that virtually all the pigments have changed.
Basically I'd agree but I don't think it's right to say that virtually all the pigments have changed colour, certainly a large number of them have though. The colours certainly would have changed almost universally even if due only to the yellowing of the vehicle, but the increasing transparency over time plays a large part too as can aged varnish.

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Old 01-11-2011, 10:09 AM
Trond Trond is offline
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Re: Vermilion Test

Quote:
Originally Posted by Einion


Basically I'd agree but I don't think it's right to say that virtually all the pigments have changed colour, certainly a large number of them have though. The colours certainly would have changed almost universally even if due only to the yellowing of the vehicle, but the increasing transparency over time plays a large part too as can aged varnish.

Einion

Sorry, my statement may not have been very clear. It was more focused on the artist pigments used having been supplanted by new ones in modern paints. It may not change the color much if mixed correctly, but it can still change the look of your paintings. You can get pretty much the same color and value by applying a gritty earth pigment transparently over a white background, or by mixing a new mars color with titanium white. It still will not look the same due to the differing textures and translucency of the materials used. To some, these things may be unimportant, but it makes a big difference to others. Fans of Williamsburg love the gritty feel of their earth colors, and if you look closely, the pigments make a very different surface on the painting. To such painters, saying that you can easily mix Williamsburg's burnt sienna from other colors would make little sense.
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Old 01-11-2011, 11:09 AM
michael harding michael harding is offline
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Re: Vermilion Test

If any of you are wondering yes I am the paint maker.

Great work Jim lets see in a few months which change, for my money I would say any genuine vermilion will change. That begs the question which is real? When I located my source some 10 years or more ago I had it checked out by friends at Birkbeck College part of London University, they informed me it was 99.9% mercuric sulphide using x-ray diffraction. So lets clarify vermilion is mercuric sulphide and nothing else and is known in the colour index code as pigment red 106 or abbreviated CI Pr 106.

Placing other mixes and pretend vermilion reds in this test is pointless, as they should be labeled on the tube as “Red” or state clearly as “imitation vermilion”. I see it a bit like wine it should be drunk on its own with no ice!

If people want a red with no history but good light and colour stability they should start another thread called permanent reds! Also do not forget if you put any old master in direct sunlight we know what will happen.
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Old 01-11-2011, 03:37 PM
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gunzorro gunzorro is offline
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Re: Vermilion Test

Michael -- Thanks so much for dropping in on the discussion! Yes, I did mix the two different types, but I think we can clearly see the differences. The brighter versions have also been declared by their makers as genuine, so the only way to tell would be independent chemical analysis -- anyone want to be a patron?

Thank you for your past generous support in this project, and for your continued efforts to bring quality paint to artists.

ly -- Thanks for the reminder! I'll look into doing the write-up and posting the photos.
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Old 01-12-2011, 05:00 PM
michael harding michael harding is offline
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Re: Vermilion Test

Jim, one way of brightening a vermilion up would be to add a brighter red say a cadmium light or a bright organic red to an existing genuine vermilion. This might throw the result of a chemical analysis since a test would also show mercury/sulphur that might lead people to assume its genuine through out.
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Old 01-12-2011, 11:01 PM
schravix schravix is offline
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Re: Vermilion Test

See if you can find Dr. Leslie Carlyle's excellent research on the darkening of HgS pigments due to adulteration with cheaper, easier to produce pigments.
Also something to take into consideration is that a single chemical compound can yield a variety of different colors; For example FeO (PBr7) appears as dozens of distinct hues.
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Old 01-13-2011, 09:42 AM
michael harding michael harding is offline
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Re: Vermilion Test

She is an old friend I did raise the point years ago with her that vermilion could have been cut with minum, red lead another pigment thats heavy and has a black phase.
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Old 01-13-2011, 10:05 AM
sidbledsoe sidbledsoe is online now
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Re: Vermilion Test

Excellent valuable information being revealed here guys, thanks very much!
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Old 01-20-2011, 12:03 AM
ly ly is offline
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Re: Vermilion Test

Quote:
Originally Posted by gunzorro
Michael -- Thanks so much for dropping in on the discussion! Yes, I did mix the two different types, but I think we can clearly see the differences. The brighter versions have also been declared by their makers as genuine, so the only way to tell would be independent chemical analysis -- anyone want to be a patron?

Thank you for your past generous support in this project, and for your continued efforts to bring quality paint to artists.

ly -- Thanks for the reminder! I'll look into doing the write-up and posting the photos.

Hi Jim
Any problem with test results ?
ly
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Old 01-26-2011, 03:36 AM
ly ly is offline
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Re: Vermilion Test

Quote:
Originally Posted by gunzorro
Michael -- Thanks so much for dropping in on the discussion! Yes, I did mix the two different types, but I think we can clearly see the differences. The brighter versions have also been declared by their makers as genuine, so the only way to tell would be independent chemical analysis -- anyone want to be a patron?

Thank you for your past generous support in this project, and for your continued efforts to bring quality paint to artists.

ly -- Thanks for the reminder! I'll look into doing the write-up and posting the photos.

Hi Jim
It's only a reminder...
Thanks
ly
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Old 02-07-2011, 01:22 AM
ly ly is offline
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Re: Vermilion Test

Hi Jim
Is there any problem to post Vermilion Lightfast Test ?
Sorry to remind you...
ly
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Old 02-09-2011, 10:03 AM
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gunzorro gunzorro is offline
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Re: Vermilion Test

ly -- No problem. Just the usual distraction: wind, rain, photo assignments, camera & lens testing. . . and a general shiftlessness.

I've pulled the samples out and have a camera sitting next to them. . .

Soon-ish.
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Old 02-09-2011, 12:35 PM
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Re: Vermilion Test

Okay! Sorry to take so long!

I'll admit, it wasn't just the photographing that delayed me. The summary of results was also a deterrent!

Here were go!

I've literally "assembled" examples for you to view, in all their redundency, along with an extraneous color bonus (a reward for your patience!).

The first shot is a two-shot panorama stitched together in PSE8 from two shots below. There is also one overall shot of the to pieces of acrylic primed poly-canvas vermilion tests.

Overall, these reproductions might show a slightly enhanced red saturation over the real examples, which are a little bit more dull. The examples are for determining broad comparison, not for exact color matching. YMMV.

As you can see, I continued (and I think concluded here) my experiment with varnishes to see if any offered particular protection from fading or discoloration. The first note I'd like to make is that all these pigments are very consistent, even those that darkened, and no amount of varnish, even with UV blockers like Gamvar and Soluvar, have made any detectable difference. The only "oddity" is the 25% Amber, which by its nature was darker and glossier than all the others.

Paint notes: 1) You might be able to detect that the Vasari has a slightly different hue than the other bright samples -- slightly shifted to a more rosy-magenta. Not a lot, but it is there. 2) Also, the Natural Pigments texture and surface produce the most beautiful dead matte surface of all the samples -- it is almost impossible to see any reflection or differences in the texture -- that is beautiful milling of pigment.

Color candidates, for left to right: Blockx, Harding, Studio Products, Doak, Blue Ridge, Vasari, Natural Pigments and RGH.

Varnishes, from top to bottom: Gamvar, Soluvar (matte), Old Holland (gloss), 25% Amber (undiluted, custom-made), and 25% Mix (diluted slightly).

Obviously, there are (at least) two types of pigment here! The Vasari is the only one listed as PR113, a combination cadmium/mercury pigment. All the others are reported by their makers to be genuine PR106, with the exception of Blue Ridge, who is listing their paint as "cadmium" until such time as it can offer conclusive proof of the pigment.

Beyond these tests, the next step would be scientific analysis of the pigment samples to determine why some are darker than others. I will gladly off these samples if someone wishes to underwrite the cost of testing. Just let me know the lab, and I'll send them the samples. Otherwise, this is the extent of my involvment in the testing and comparison of vermilion pigments. (Whew!)









The final is in response to a different thread (if I ever go looking for it, I'll update it) about supposed genuine Chrome Yellows fading (lead chromate, no longer generally used in commercial oil paints). The result is as can be seen: no fading. Sorry to disappoint! These are Winsor Newton Oil Paint, circa 1960s. I include their Chrome Green which is a combination of Chrome Yellow and Prussian Blue. You can see a little fading on the opaque section, but I attribute that to weathering, not sun-fading, as you can see the transparent brushed paint on the right side has not faded. The yellow samples are laid down the say way: solid opaque on the left of the sample swatch, and thinned semi-transparent on the right.

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Old 02-09-2011, 01:00 PM
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Brian Firth Brian Firth is offline
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Re: Vermilion Test

Jim,
Great tests as usual. The results are what I expected, the proven real vermillon darkened, while the other "vermilions" (from companies that don't comply with ASTM standards) didn't. There is really no need to test these pigments, any manufacturer of real vermilion paint should easily be able to provide an MSDS sheet from the manufacturer of the genuine vermilion mercuric sulphide PR106 pigment (there's only one or two in the world). Any company that can't is hiding something, it is up to them to prove their product is real, not us the consumer. Real vermilion darkens in sunlight, period. That says it all to me about the other "vermilions". Also, as a note, Blue Ridge has stated publicly and privately that their vermilion pigment was not genuine.

Also, your chrome yellow tests match mine, as I tested the Chroma Archival Superchome yellows and they also proved perfectly lightfast.

Also, as previously debated, the amber varnish did nothing to hinder darkening of genuine vermilion.
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Old 02-10-2011, 10:53 AM
ly ly is offline
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Re: Vermilion Test

Hi Jim
Thanks a lot.
Now I can safely use Vasari CadVermilion.
Also I will use safely Chrome Yellow from NP(which is coated chrome yellow
that is a lightfast version and may be WN used this type of pigment).
I'm not shure if I can use safely Prusian blue as most tests done by others
shows it is not so lightfast.
Thanks gain
ly

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