U of S | Mailing List Archive | alt-photo-process-l | RE: Gum Calibration 3 (Dark Tricolor)

RE: Gum Calibration 3 (Dark Tricolor)

Thanks much Marek. Especially about roller coating. That seems to use
quite a lot of paint -> will definitely resort if I can't manage to coat
as evenly as I'd like it to be... For now I'll continue with brush coating
-> thinner!

I'm just doing a test by diluting the stock pain/gum solution. I'll see if
that's too little paint (probably it'll turn up as you say).

You're right about brush and sprayer but I want some consistency right now
(and less stress).


27 Ekim 2008, Pazartesi, 5:39 pm tarihinde, Marek Matusz yazmış:
> Loris,
> By all means experiment. It is the best way to learn gum.
> Just looking at you note and remembering previous posts I have a few
> comments.
> It seems to me that diluting your stock pigment solutions with additional
> gum will lead you to weakly pigmented layers. I can only judge that basis
> my use of Daniel SMith pigments, but somehow I do not suspect that other
> brand contain 2x the amount of pigment. Your statement that individual
> layer are too dark and hence the need to add more gum leads me to the
> conclusion that you coating is too thick. That would also agree with your
> difficulty of smooting the layers out. It is just about impossible to
> smooth thick layers of gum.
> I would suggest dilute your stock solution with dichromate 1 part stock +
> 1 part dichromate and skip the additional gum. Measure the amount of the
> mix that you use to arrive at consistent layer thickness.
> FOr coating pour the mix on paper, quickly brush it in making sure it is
> spread all over the print and start rolling with the foam roller (I roll
> in one direction up and down and them side to side). Keep rolling applying
> less pressure as you go. You will end up with a very smooth coat (my
> practice is about 1 minute). If you keep rolling too long the mix gets too
> tacky you will start see roller marks.
> The roller has to be damp, but not too wet. Try coating 5-6 sheets at a
> time. By the time you are done with the first sheet the roller will have
> the correct dampness to it and would have picked some paint for a steady
> state work. By the time you get to the 6 or 8th sheets you will have the
> feel for the coating.
> If the roller becomes too wet (long rolling times) just roll it over dry
> paper towel.
> Remember that the most creative tools for gum are the brush and sprayer
> bottle during development. They might help you more then overly compicated
> negative systems.