Re: clearing dichromate stain

[Judy Seigel <jseigel@panix.com>]

I'm disappointed that Katharine hasn't yet explained who said "It's OK to 
eat dichromate," since I hope to be first to fly out on my broomstick 
(waving my bonnet) to excoriate that fiend.  However, as I enjoy Chris's 
current reports from (mecca?), I have a couple of comments to add...

For one, I wonder about all this hooha about dichromate/pigment stain. I 
have a theory in fact, which I will reveal soon. Meanwhile,


an 2007, Christina Z. Anderson wrote:
> Need I mention that on this list and in my book I have debunked what I call
> my top ten gum myths--actually 13 or so--so where is it that I have
> promulgated myths? In fact, if you remember, one of the myths of "don't boil
> gelatin" when sizing which you either adhered to or still do, I disproved by
> boiling gelatin ad nauseum and then sizing paper with it, during grad
> school, 30 LARGE prints, that showed nary a problem.
In this, Chris, my experience is different... It's possible you have some 
other factor (water?, personality? grouchy? blonde?) that cancels that 
problem, and it would be marvelous to comb it out.  But I am ALMOST 
prepared to say that I know enough about gum printing to be able to tell 
when overheated gelatin is the variable that's causing the glitch... 
especially when recoating has solved it. (Maybe it's your brush coating 
vs. vat sizing?)

But speaking of which,

> As far as the statement in question, where the author said "light works the
> same as heat"--in gum practice...
> Heat and light both create insolubilization of gum.  Kosar agrees. Hey, I'm 
> game to bake an unexposed gum print in the oven and see if it develops--you 
> can, too! We can call ourselves the Betty Crockers of gum! And, if you reread 
> that post, I was ASKING chemists if this made sense, not perpetuating myths.
No need to give me Kosar... If the neo-cans hadn't stolen my book I'd 
quote stuff he says that is irresponsibly 3rd-hand vague, and anyway never 
tested on gum, which, by my bonnet, is NOT the same as carbon in many if 
not most) instances.

However, I note that when a student did a gum print that absolutely would 
not "develop," but stayed overall "fog" despite all efforts, the diagnosis 
was almost invariably that the coat had been "dried" with a hair dryer on 
hot, up close (as I often caught them doing), which they of course learn 
to do with other processes, eg platinum, so they don't *hear* me when I 
warn against it. The emulsion was, as I explained "cooked."

However I again point out that in 100 years of gum literature I've seen no 
"problem" with residual dichromate stain, in whatever color.

> Needless to say I spent days writing and rewriting this post to tone down its 
> acerbity and frankly, this is as good as its gonna get.
> Chris
Actually Chris, overnight is usually enough, or I've found it so... and 
gets the thing out of your craw (not to mention yr bonnet).

But now I have to write about PAUL ANDERSON... (hehheh)

Judy