Paint goes from opaque to transparent in 3 months?

Alan P. in OC · #1 09-03-2012, 05:06 PM

Hello,
About 3 months ago I bought this paint (Blockx Turquoise Green).

I painted a square of it on a scrap of canvas paper, over a black "X" in marker to see it's opacity level.

The paint was so opaque then it completely obliterated the "X". Today, when sorting through all these test scraps of paint charts, I found the test I did on this paint, and the color is completely transparent now. It's also a little lighter than another test I did with it a week ago, but it's the transparency that flips me out.

Anyone experience this before, or have this color? I'm not upset that it's transparent, really, just surprised. It was bought to glaze over the hood of a classic car painting (it was the perfect color and I got it cheap from a sale at the Italian Art store).

Any thoughts or comments welcome.

**!becca** · #2 09-03-2012, 05:33 PM

Alan, thanks for sharing, and do show a pic of your test square! I am not totally surprised as I have noticed the same type thing on a couple of my paintings where the drawing phase suddenly decided to show through, but it is worth noting..

Curious, how thick an application did you make for your test? Would be interesting to see if this persisted when it is mixed with other colors..Wonder if it is particular to Blockx of if other names with this pigment have the same results?

I am guilty of watching my paint cure on my canvas and observing the metamorphosis til it cures..

Coastal · #3 09-03-2012, 05:35 PM

Hey Alan
Could it be the ink of the "X" ?
Maybe it burned through the opaque a few days after drying and you just re looked at it?

**!becca** · #4 09-03-2012, 05:36 PM

John, are you implying the ink "bled" through the paint? If so, maybe the process needs repeating!

Coastal · #5 09-03-2012, 05:41 PM

Yep I lost a painting due to the ink of a marker and it would cover opaquely for a while then bleed thru

Ron Francis · #6 09-03-2012, 05:42 PM

I was going to ask the same question.
Did you also do other tests with the black marker where the x didn't show through?
When you say completely transparent, surely you don't mean that it has lost it's colour.

**!becca** · #7 09-03-2012, 05:44 PM

Quote:

Originally Posted by Coastal

Yep I lost a painting due to the ink of a marker and it would cover opaquely for a while then bleed thru

This is interesting,...and I am certain was frustrating as well!

**NancyMP** · #8 09-03-2012, 06:25 PM

...and I was warned that carbon pencil would bleed through! That ink you used must be powerful! I don't have that brand or color, so I might be out of line, but drawing materials for oil painting in my studio are limited to pastel pencil or vine charcoal. The only ink I've seen recommended for oils are the more translucent inks like walnut ink. I have some of that, but I've always found it easier to draw with pencil or brush.

You might try that experiment again and mix the paint with a small bit of titanium white?

**!becca** · #9 09-03-2012, 06:39 PM

I think it should be repeated exactly as before once with the marker and another say over thinned paint lines, like I use..and I will say in some cases they have shown through..

Alan P. in OC · #10 09-03-2012, 06:42 PM

Unfortunately I won't have my camera for a couple of days, it is being borrowed.

I looked at both tests again: the old one (3 months) is slightly lighter in value and chroma, and the X is about 90% visible.

The new one, painted 9 days ago, is slightly darker and lower chroma, with the X about 10% visible (although in less-than-stellar lighting conditions is virtually nonexistent).

They were both painted in an even, thin-ish layer over a black-sharpie-marker X. Fortunately I don't use this to draw out anything, just make X's on my color charts to determine opacity.

The vast majority of my 27 or so colors are at least partially transparent, but I do have some cadmiums (cad purple and cad red orange). These are also 3 months old and the X shows through just as clearly as on the paint in question. I cannot remember whether these went on as opaquely as the Turquoise paint, but I suspect they did.

As I just completed the color chart the other day with another opaque color, cobalt blue, I'm in a position to keep an eye on if this also goes transparent or not. Right now, 9 days later, the X is only about 10% visible; I'll watch it in the future to see if the X becomes more apparent.

The chart I'm making does have some tints made with titanium white, but they are all newly applied and opaque right now.

I never believed in any kind of bleeding through before, but these were just 1 layer of paint on canvas sheet over a very dark marker. It surely may be a case of this sharpie migrating through the surface....

I suppose I can try to reproduce this with fresh paint over a dark painted X, using ivory black or something. Wish I can show you a pic, hopefully I can have one up in this thread by Wednesday afternoon.

Thanks for all the responses and opinions

.

**!becca** · #11 09-03-2012, 06:47 PM

Alan, thanks and I look forward to the pic, personally I may be busy til wednesday afternoon anyway.

It is great you have other samples to compare.

Spudboy · #12 09-03-2012, 08:06 PM

Cobalt Turquoise being one of my favorite pigments, I look forward to seeing the pictures of what's going on!

Coastal · #13 09-03-2012, 10:04 PM

Looking forward to the car painting

Re 2nd coat of paint over the "X" One insidious fact of stains is that the new wet coat of paint reactivates the dry "X" and that now burns thru coat number #2 Anyway it sounds like the transparent or not is more the question

karenlee · #14 09-03-2012, 10:20 PM

[quote]The vast majority of my 27 or so colors are at least partially transparent, but I do have some cadmiums (cad purple and cad red orange). These are also 3 months old and the X shows through just as clearly as on the paint in question. I cannot remember whether these went on as opaquely as the Turquoise paint, but I suspect they did.
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If I am reading this correctly, the Sharpie is showing thru all the paints you tested, including cadmiums? I would repeat all tests as suggested, using a black paint (e.g. Ivory black) X underneath rather than a Sharpie, and see what the results are.

mrking · #15 09-03-2012, 10:25 PM

Quote:

Originally Posted by Alan P. in OC

...but I do have some cadmiums (cad purple and cad red orange). These are also 3 months old and the X shows through just as clearly as on the paint in question.

That answers your question right there, cadmiums are highly opaque. If you can see the 'X' through the cadmium samples then the sharpie has bleed into the paint layer.

I would not worry about PB36 paint on your canvas unless one was to sketch in sharpie. :P

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