Re: dichromate stain

> Katharine said, snip: This discussion just illustrates how unlikely it is
we'll ever arrive at
> any kind of usable truth about gum printing by talking about it. It's
> easy to make gum prints; the difficulty arises when someone tries to set
> out a rule, or to try to explain differences in observations.

Yeah, this is why the title of my book is going to be "Postmodern Gum: Do
As I Do But Don't Believe a Word I Say" :)=)

> Katharine said: rules and explanations almost invariably turn out to be
wrong, or at
> least right only for a very particular set of circumstances, so not
> useful for gum printers in general.

I respectfully disagree. If I may wager a bet, this list does not give a
hoot about "one gum truth" but about a set of variables which may or may not
be the answer. Clues. That is how I learned gum--troubleshooting had a
number of answers listed for every problem. Maybe only one answer was my
cause, but that did not disprove the others. As I've said before, one black
swan does not prove there are no white swans, only that there are more than
one type of swan.

The fact that (I wager here) probably 90% of gum printers experience stain
at least once (gross understatement) in their gum career leads me to
believe it is a bona fide issue worthy of discussion. Thus, knowing the
possible contributors of stain as exposure, type size, type paper, type
dichromate, development, strength dichromate, etc. etc. is beneficial.
There cannot be one cause of dichromate stain across the board because of
the incredible variables in the gum process.

> > Judy said: Another reason I have less staining is probably that my
development times
> > tend to be long. I gather that some folks develop a half hour or less...
I
> > usually develop an hour and up... and I have noticed that the really
long
> > soaks come out wonderfully white -- and assume that, at least in part,
> > that is why I rarely if ever need a clearing bath.
>
> Then Katharine said: Funny, Christina was just arguing yesterday that the
reason she GETS
> dichromate stain is because she exposes hard enough to require longer
> development, and today Judy argues that she DOESN"T get dichromate stain
> for the very same reason, which just shows how far we are from any
> useful explanation for this.

Correction: my variable is not development, but exposure alone. Judy is
talking about development. I usually develop less than an hour, but the
dichromate stain I was referring to was on my test wedges that were
overexposed and developed longer, and I said the dichromate was more
apparent on the paler pigmented wedges. Regardless of whether stain is
apparent or not on my wedges, I always clear them.

To observe dichromate stain on prints I will clear half a print and see the
difference. Always intriguing, and that even goes for the prints that don't
look stained.

That said, I rarely, since switching to the lower dilution am di, feel a
need to clear my prints, and, in fact, don't much since Sil Horowitz said,
no problem, and since most are of the camp "If you NEED to clear, then you
can". With unsized Fabriano Artistico which I am currently using, I do
notice more of a tendency to not release dichromate.
Chris
Received on Mon Jun 14 16:18:30 2004