I started my first acrylic painting today with PY100 tartrazine, PR122&BV10 opera, PB15 cyan. They mixed colors very well but there is an insurmountable problem. I've had better days. DonJ

I made a tube of Tartrazinez w/ a red/brown transparent to match PY150 to go with my PY100 Tartz that does the job of PY153.
The pigment I described to Spectra Colors to make the PY150 has too much red in it, but it does make a cool yellow transparent glaze. The PY100 test on a gessoed palette and primed canvas had no pick-up after it was dry. The Opera pigment dissolved in Ammonia first made a perfect acrylic pigment. I must make a tube of it. Dissolving the Opera pigment in alcohol disolved the darker BV10 compound only, I couldn't use it.



I'm going to finish the painting, it's not on line yet but will be when I'm done with it.
http://www.realcolorwheel.com/Jacaranda2013MakawaoSchoolCrossing.htg

3-7-13, Results of yesterday's tests.
Tartrazine on plate, w/o poly = some pick-up.
With Poly, 1% pick-up

Golden Gesso on plate, tartz only = no bleeding pick-up
Golden Gesso on plate, tartz + poly = no bleeding pick-up

Ammonia dissolved tartz mixed with white acrylic = looked like yellow colored paint while it was wet and soft.  The paint looked orange when dry with a lot of pick-up, the pigment had floated. When it was surface wetted again with water it returned to yellow, only while it was wet.

Without the ammonia and mixed with white acrylic it did not bleed (.5) but was the color of gamboge tint, not cad yellow.
I didn't test it with alcohol.

Tartrazine on plotter canvas or paper did not bleed with or w/o a polyurethane coating = no bleed, no pick-up.

Opera dry pigment and alcohol dissolved the B10, so it could be separated to a darker magenta color closer to PR122.

Using ammonia broke down the pigment where water by itself would not. It made a fine tubed transparent warm magenta pigment, leaning to the PV19 side.

Thank you for the update and your help. I am glad that now I have a yellow mixture won't bleed. Also it sounds like the poly does a really good job at locking everything in.

Admin wrote on Mar 5^th, 2013 at 3:02am:


My guess is it will smear. This is what happened to me even after a third clear isolation coat (although not polyurethane, just glazing medium). I've basically ended up washing the painting with soap and water, got rid of all the yellow smears, and re-painted those areas with a different paint.

Acrylics can take a lot of punishment like this and it's part of the reason I like them. According to Golden, washing the painting between the layers may actually improve adhesion, especially when using slow drying acrylics. The reason is that during drying, surfactants used during the manufacturing process raise to the top of the acrylic film and make it less adherent. It takes about a month of drying for this to happen.

I found a white plate. Acrylic didn't mix as well in to the egg white. It mixed very well into the yolk. After the tests I may work on the % of each. 5:44Pm, One pure yolk, one pure egg white, one 50/50 of each, one with 50:50 dye and white tubed acrylic.

I was looking earlier at Spectra Colors. Can you please confirm if this is the right one?

http://spectracolors.com/

I had to register to view their product codes, but even then I can't tell which one I should use. There are several product categories, and for each category they have a PDF file with the product codes. There are also several "Tartrazine Yellow" products. I assumed it's in powder form, so I looked at the FD & C list. They seem to be the only ones listed as powders. There is a "Yellow 5" within this category that looked like it's the right one, but it says it's only 20% soluble in water, so it's probably not that one.

Could you tell me the product code you are using?

Thanks,
Vlad

Hello,

Maybe my problem is that I've mixed too much tartrazine powder into the medium. If the acrylic medium, when drying, "squeezes out" the dye, and also if the support is relatively non-absorbent, then the excess dye would have nowhere to go than lift up to the surface.

It does say on the box "dye content more or equal to 85%". Perhaps this can explain the price, aside from the fact that it's "pharmacology grade", whatever that means (I am guessing purity, consistency between batches, etc.). As a bit of trivia, they also have the "analytical grade", around the same price for 25mg. Yes, milligrams. It could also be that the less pricey one has a lower dye content, and that's why you don't see any bleeding with yours.

I will mix to get a cad yellow light hue, and test. If I don't get the bleeding with a lighter hue, then perhaps my theory is not that far off.

If you have some time, would you be interested to test on a non-absorbent surface, such as a plate? With other acrylic colors, once the acrylic film is dry, you can peel it off and there is no bleeding on either side of the film (let's call them "air side" and "plate side").  Liquitex, for example, calls these dried paint films "acrylic skins". I am curious to see, once you peel the dried film off the plate, will the plate side show any bleeding when swiped with a wet rag or paper towel?  This I think would be important to know from a conservation perspective - if the tartrazine sits loose between the layers of paint, how does it affect the adhesion between the layers?

It is possible that with a gessoed surface, being slightly porous, the tartrazine stains the gesso underneath, and the acrylic coat is just a barrier. When used in a printer, I suspect it's the same, the tartrazine dye will stain the support.

I'll let you know how my less concentrated mixture turns out.

Thanks for working with me on this.

Vlad

Hello Don,

Thank you for such a quick reply. I got my tartrazine through a pharmacology lab from Sigma-Aldrich. Here is the link:

http://www.sigmaaldrich.com/catalog/product/sigma/t0388?lang=en&region=CA

It seems to have all the properties you mention. On black it's transparent. In higher concentrations it's orange. When thinned it's a very bright yellow, toward the yellow-orange and not toward yellow-green like the hansa yellow light for example. When mixed with magenta it gives an intense red.

I can order from the supplier you are using and try, however I am wondering what can be different. To me, it seems logical that if it's the same molecule, it would behave the same way, regardless of the supplier.

What kind of acrylic medium have you used for mixing? This is the other variable, although I agree it seems less likely to have an impact.

Thanks,
Vlad

Hello,
Thank you for the reply. I have seen the page - that's why I wanted to give it a try. The problem is that I am able to wipe the yellow off once the paint is dry. I've posted a more detailed description in a different section - I didn't see that you had already started the discussion here.
My post is here:
http://realcolorwheel.com/cgi-bin/yabb/YaBB.cgi?num=1362346829
Thank you,
Vlad

(Hi Vlad, I moved your (this) post to the Acrylic Discussion topic. Don)

Hello,

I am trying to make some transparent yellow paint by mixing tartrazine powder into a clear acrylic medium. The medium I used is Liquitex glazing medium. I've used two methods so far. One method was to mix the powder right into the medium. The second was to dissolve the powder into a small quantity of water first, and then add the medium.

The problem is that the dye doesn't stay in the medium once the paint dries. If I go over the paint film with a damp rag, I can wipe the yellow. If I insist, I can pretty much wash all of it. It doesn't matter how long I leave the paint to dry. The medium stays on the support just fine, only the yellow dye goes away. It's as if the yellow raises to the surface of the acrylic film when it dries.

I've also tried to paint over the dried yellow film a few coats of clear medium, hoping that the ear medium will act as a barrier, but without success. Even after three clear coats of medium, I can still wipe yellow from the painted area.

I am looking for suggestions.

Thank you,
Vlad