I do have a couple more comments on the "scientific" method, which
originally came to mind with Dave's & Wayde's comments, but will fit well
enough here...
On Mon, 8 Jun 1998, Jeffrey D. Mathias wrote:
> The best method is as Judy suggests. Investigate one parameter at a
> time. The multitude of variations can be reduced by making some careful
> assumptions to eliminate variables. For example, include all the
> ingredients necessary to make a gum print. It's nonsense to leave
> something out.
It occurs to me in this context to bring up "Occam's Razor," which claims
that the *simplest theory* should take precedence, although we see in gum
printing as in microbiologicalcellular research, it almost never does (and
I'm going to write an info-torial on that very claim in my next issue).
My suggestion to students is to try out a couple of papers, choose
one you like and continue with that. (Do as I say, not as I do, I am a
paper junky & have trouble settling down with just one.)
I can't and don't want to get EVERY variable under control in *printing*
-- a lot of what I like about gum is the accidents, or the gifts the
process hands me that I could never have planned or come up with on my
own. True, this means a lot of waste -- but I'm not meeting a quota. What
I test for is general knowledge -- findings are usually counter-intuitive,
or anti-Occam's razor.
I think the most controlling variables are (in no order):
1. the paper (as noted)
2. the size or lack thereof on the paper & nature of the size...
3. whether it's a first or subsequent coat
4. the gum arabic (different gums react VERY differently with pigments &
sizes)
5. the pigment....by brand.
Though maybe THE major variable is development... but because development
is so flexible, you can go easy on other controls (as long as your basics
are working) and tweak or noodle by length of soak or water temp, or spot
development, or whatever.
In a sense, though, I think I may do Wayde's & Dave's scientific method,
because when I'm in test mode I generally run 26 strips at a time, say 13
papers with one variable for each (size-no size, method of application,
whatever is on the docket).
But that's just if I have a question in mind, eg., is this size or this
gum any good, and with what. I would NEVER try tests like that for
regular printing -- that way lies madness. When doing a real print, I like
to wing it.
> I wasted a couple months with Anderson's test back in 1991. I was
> investigating gum as a way to add color to a platinum print. The result
> was some despair over the Gum process. It would have been nice to see
> Judy's method back then. Maybe some "rainy day" I'll re-attempt some
> Gum by way of Judy's techniques.
You get a lot of rain there in Florida, maybe? Sometimes my students have
had platinum before my course (usually it's the other way around), and
have some "out-takes" -- failed, usually too-weak platinum (or rather
palladium) prints. These are terrific with a layer of gum on them. If the
paper wasn't preshrunk, register is a problem, although with 4x5 the
difference is usually negotiable.
cheers,
Judy