Regarding allum.

Acrylic Marbling
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Posts: 8
Joined: Mon Dec 11, 2017 6:00 pm

Regarding allum.

Post by myra_myra »

when I prepare my allum I add a 4 tablespoons to 1 litre of warm water (according to the Jaqard instructions), and I stirr it well and them get to work soaking my sheets in the solution.

anyway, I wondering if I've dissolved the allum correctly, cause the spilt allum solution leaves a white residiue on the various surfaces it comes into contact with, is that correct?

I've been doing this for about 10 years and when I do little tests with/without allum I can't see any difference!
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Joined: Thu Jun 29, 2017 11:12 am

Re: Regarding allum.

Post by SouthHillKaren »

Alum solution, when it dries, leaves a very fine crystalline powder behind. This is normal. The whole point of putting alum solution on the paper is to get a very fine layer of tiny crystals deposited there. The alum kind of grabs the pigment and holds on to it. As you have probably found, the pigment is not made permanent by the alum, just helps it grab on. If the alum solution is too strong, the powder will dry too thick, and it can actually act as a resist (pigment can't get thru it to the paper). Sheets need not be soaked, just dampened with the solution to get that little layer of crystals on the side you want the pigment to go on. Some people spread the alum solution with a lightly dampened sponge and let the paper dry flat. I dip my paper quickly, one side only, and let it drip dry. I run a paper towel along each hanging edge, because sometimes the solution gathers there and makes a little resisted (pale) strip. A lot of papers, if very absorbent, don't need alum at all. It is up to you to choose the look you like. Alum makes it possible to use some smoother papers, or ones with texture, or unusual materials. I feel application of alum usually gives me a sharper print, and tends to help some of the more difficult colors hang on.
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