U of S | Mailing List Archive | alt-photo-process-l | Re: Stock paint: gum solutions

Re: Stock paint: gum solutions

Kees and Loris,
I use mostly a 300 or so g. gum in a total volume of 1000 water, a 14 baume.
I also mix a thicker gum I use at times.

I'm too lazy to do the math but considering each 8x10 only has about 1/2 tsp
coating which is 1/4 tsp gum/pigment you may be right. So let me figure this
out--if I am making one 8x10 I mix up a tsp of mix, some to "charge" the
brush.  In that tsp I usually use 10 drops of thalo/gum out of that 60 ml
container, or less.  This is plenty strong!  That would mean that doing
individual 8x10s I could conceivably get 120 prints out of a bottle of mix,
and more because when I do 8 at a time I don't charge the brush 8x.  Thalo
goes a looonnng way.  Other colors not so much. So a conservative estimate
would be 120 prints out of 60ml combined solution but you can check my math
on this.

At time of use I cut my pigments with plain gum--thalo gets cut as much
as 1+5, yellow maybe 1+2, magenta maybe 1+3, depending.
I don't understand this; you mean you further cut paint:gum solution 1+5
with gum? Then,

* 15ml paint in 60ml => 0.250ml paint in 1ml stock solution,
* 1ml stok + 5ml gum => 0,042ml paint in 1ml coating solution
(disregarding dichromate part)

That would mean you can make something like 230 8x10" print per tube of
Phtalo (Assuming 3ml coating solution per 8x10" and 1:1 gum:dichromate
proportion...) Can you really make that much print with a tube of Phtalo,
or am I getting it wrong? (It seems like too much dilution to me.)