Re: URL for platinum gum comparison

>yves said: I don't argue about your choice of using a platinum print but I
>think it
> would be more fair to do both prints on the same paper IMHO.>
> Would it be fair to say that you don't think it is possible to reach the
> same Dmax with gum (multi-exposure included) then what is possible with
> Platinum?

Sorry, y'all, for taking long to answer questions. How nice to see such
discussion pertaining to alt and not the "p" word.

I am going to have to answer several emails at once here because final
grades are due and I fly out tomorrow for my daughter's wedding. If I seem
scattered, let's just put it that I have yet to buy a dress for it (but
hmmmm....I have time to gum print....what's wrong with this picture?)

Well Yves, hopefully when Sandy sends his carbon it is on a paper similar to
Fabriano Artistico because that is all I use. You are right, the pt/pd is
on Platine, a very smooth paper, and the gum is on FAEW.

Let me reiterate: the whole reason of comparing gum to platinum (an analogy
would be big fat honkin' cantaloupes with tiny delicate persimmons) was to
give gum a very unfair disadvantage--the worst case scenario. Sandy is
sending me a carbon in the mail and I will redo the same test in comparison
with a carbon print.

Dmax: I'm not sure, I don't have a densitometer but the scan should show
that the blacks in the shadow are carbon black, as black as black can be,
and the whites are paper white.

What I found with the test is that you can get a fully tonal one coat gum,
but in order to get a fully tonal SMOOTH one coat gum from dmin to dmax,
there is a fine line
between including enough pigment to get the deepest black and too much where
grit starts happening. It should be visible from the 1g/100ml pigment load
that the gum coat is very smooth and fine, but unsuitably dmaxed. The final
print at the bottom right, curved, albeit tonally fine, is gritty.

Granted, i used powdered pigment just plopped in the gum and shaken, so I
did not grind with a muller or an electric stirrer or some such thing, and
carbon black is a very oily substance, so "grain" or grit could be a
function of my mixing technique. The print looks good in person but
certainly doesn't compare to a pt/pd, you know?

Marek, I don't know why the 3g uncurved gum print shows less grain as in
reality it is very grainy. You'll have to trust me on this one.

One thing about scans and computers and monitors--I included the pt/pd
because all of the tonal range is there in that print. So you have to
believe me, if your monitor doesn't show it. For instance, when I view
Katharine's gums on my monitor, they are very contrasty, lacking detail in
the highlights always. I assume she knows how to gum print and it is my
monitor--I'm on a laptop. You computer gurus can explain how a laptop
monitor differs--I think it is brighter, no?

So, I'm not finished with this experiment. I have proven to myself that you
can get a fully tonal one coat gum with suitable dmax, as Judy says, with
lotsa pigment and a longer exposure and slooowwwwwww long development. I
have not tried her increase of dichromate as outlined in the One Coat Gum
article p. 33 Issue 6. If I do then I would have to adjust my curve. I did
have to increase my normal exposure to 9 minutes which, coincidentally, is a
50% increase as she has suggested in said article. I did also increase my
development time and did not spray or brush off highlights as I usually do
for sake of consistency between test prints.

But I need to redo and compare to carbon AND use tube pigment to see if the
grit is a function of powdered pigment, my mixing technique or just the way
it is. I still feel it is possible to do so without grit, but my guess is
that I will NOT get the smooth, glossy tonality of the carbon transfer
because of the inclusion of gelatin into the mix. Maybe the real test would
be to try a gelatin/gum mixture for the print. My thinking is gelatin makes
for a firmer, glossier layer.

At the very least, I've had a blast!
Chris
Received on 05/02/06-09:45:48 AM Z