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

Re: Stock paint: gum solutions

First of all, thank you very much for answers!

Will reply in a single post by quoting relevant statements. See below.

> ...
> I mix all pigments 15ml tube in a total volume of 60ml because that is
> the size nalgene bottles I have.

I will arrange nice, open mouth, effectively sealable containers for
storing stock paint:gum solutions, as soon as I figure out the max. gum
amnt. per tube (=dilution) I'm going to use.

> 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.)

Thanks, and have a nice trip to Missoula!

> ...
> You do have very similar cyan and magents dilutions and as I noted
> I did not ever use your yellow.

You dilute your yellow much more than mine. That's probably because of
their different visual range (VR) values . VR = (from handprint.com) "the
value of the masstone color subtracted from the value of white paper, in
steps of a 100 step value scale", Schmincke PY151 VR = 11 (read as 100 -
11 = 89% lightness, as I get it) whereas Daniel Smith PY15 VR = 25 (100 -
25 = 75%). Since my paint is much lighter than yours, I feel to dilute it
less. If not, it would be overpowered by magenta and cyan, probably...

> I seems that your concentrations would be about 2x as much as I use
> and that would give you very strong and saturated prints, somewhat
> difficult to balance midtones, higlight and shadows in my opinion.
> AT these concentrations I run into some stain issued. I prefer to
> work in somewhat weaker layers and add pggment in more then 3 layers,
> on the average say about 5. You can always improve a prints that is
> too light with another layer or two or three.

Thanks for the notes. I look for exaggeration right now, may use less
concentrated dilutions later (and without disturbing my original recipe -
by just adding more gum to the stock solution while mixing senzitizer). On
the other hand, I aim to finish the print (and getting convincing blacks)
in just three layers.

> You are a fast learner and progressing well.

Thank you very much!

> Loris, I mix my stock mixes by eye rather than by quantity, but just
> eyeballing your amounts I'd  agree with Marek that your paint/gum
> ratios seem on the high side for tricolor. Since the PY 151 is a weak
> pigment, it's possible 1:2 might not be too far off,   though I've
> not used PY 151 beyond an initial test because it's just too light a
> yellow for my taste.  My ratios for PV 19 and thalo are somewhere
> between yours and Marek's.

That's assuring, will dilute the paints a little more then. (About this,

> While I would agree with the ranking of amounts for these three
> pigments (most for PY151, middling for PV19, and least for thalo) you
> would never find me making general statements about relative amounts
> of "yellow" "magenta" and "cyan" because pigment strengths don't
> cluster in hue ranges that way, in other words yellow pigments aren't
> generally weaker than magenta pigments aren't generally weaker than
> cyan pigments; they vary all over the place.  For different pigment
> combinations, it could go in  different orders.

Sure, I devised those figures accoring my printing experience (eyeballing)
then saw the article in handprint.com and the table labeled "Paint
Dilutions For Maximum Chroma" was in parallel with what I experienced. Of
course, I'm aware that paints can differ considerably brand to brand, I'm
just trying to find a good starting position and fine tune from there, in
just few steps.

> As Bruce McEvoy describes so competently on that page (which I hadn't
> found my way to before-- what a wonderful site; there are layers and
> layers of information to discover) there's a wide variability between
> pigments and even between brands of pigments as to how much pigment
> is required to achieve an optimum luminosity/color saturation, and
> that's why I mix by eye rather than by measuring.  I check that the
> gum/pigment mix is at optimal color saturation for that particular
> pigment by brushing it on a scrap of paper and comparing to standard
> swatches that I keep.

Unfortunately I can't trust my eye that much -> to me the most difficult
part (also, at least 50%) of "painting" is knowledge of color theory and
mixing paints.

> ...
> I don't find it necessary to print more than three layers to achieve
> a full tonal scale in tricolor, but I also think that printing with
> more layers of a lighter pigment mix gives a lovely delicate effect,
> so it really depends on the image and what you want to do with it.

More than 3-4 is problem to me right now, I'm clumsy and I feel that every
layer increase the possibility of messing the whole work in a logarithmic

Thanks much.

> Are you all using a 1:2 gum mix? Otherwise we are comparing different
> mixes.

Mine is 1:2, can't speak for others but IIRC, others were using similar
gum strength (w/ small variation).

> My stock solutions are more or less the same as Marek's, a 15ml tube
> in 150ml gum (1:2 from lumps).