Re: clearing dichromate stain
Dear all, Please forgive a cut and paste from a couple posts: 1. Katharine said:
...archives I can tell you that in side by side tests, 5% sodium sulfite worked as well as 5% potassium metabisulfite but took longer to clear (the metabisulfite took 5 minutes and the sulfite about an hour).
Katharine, if the above is true, why wouldn't potassium metabisulfite be "infinitely better" or am I missing something? Who wants to clear for an hour? 2. Mark Nelson said:
Katharine said:I would think a review of the historical literature would be quite interesting regardless of the fact that there might be inaccurate statements. Documentation of the changes in "accepted practice" over the years would be quite valuable, along with what caused those changes, especially if it included an evaluation of what turned out to be fact or myth.
"Yes, it's a very good thing to try to separate fact from myth; that's
been my sole project in the now nearly nine years I've been
contributing to this list. And I would applaud Chris's effort, if I
could see that there actually were a critical evaluation based on
science and fact which clearly separates myth from fact.]However,
this doesn't seem to be the case; in this case misinformation from
the past is continuing to be propagated on into the next century
rather than weighed and corrected. Just for one rather trivial
example, the statement that's attributed to Sil Horowitz, that in
dichromate stain, the dichromate is "fully oxidized" and therefore
inert. If Sil Horowitz said that, he's an idiot, but I'm completely
comfortable saying that, because I don't think he is an idiot, I
think it's much more reasonable to assume he was misquoted. The only
way the first part could make sense is if he meant the yellow stain
where the unreduced dichromate is trapped in the paper or the size,
but in that case the second part wouldn't make sense; such a stain
couldn't be considered inert. Anyone with any knowledge of the
chemistry of the process would know that it's a nonsense statement as
given, and would either check with Horowitz to find out what he
really said, or at least drop the secondhand citation from the
listing, since it's obviously a misstatement of fact."
Katharine, aside from the fact that Sil is not in the historical literature,
I have said that Sil Horwitz said it is not necessary to clear.
How is that misquoting Sil? Whatever is left over in the print after
development is no longer a problem. I am assuming, in your perfect gum
practice such as it is, that you have completely developed your prints, no?
Yes, I am talking about YELLOW stain being transformed to PALE GREEN in
sunlight--what is incorrect about that? Now whether my term "yellow" is
actually yellow orange, yellow brown, bright yellow, puke yellow, but never green yellow, it is whatever is left over in the print after an hour development. And my
source--"PF"--is none other than Post Factory, and Sil on the list.
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. Gee, some of those
prints are even in shows in Corpus Christi and California this month/next.
And I am accused of not separating myth from fact? Not putting my time where
my mouth is? Would I recommend that students boil gelatin? Of course not.But if they do it is not the end of the world.
There is one thing to discredit information, a wholly 'nother
to discrediting the person--as my lawyer husband says, "ad hominem". In my
case "ad wominem". (that's a JOKE.) I take [loose quote] "spreading misinformation from the past and not weighing and correcting it" as a personal critique of my research and I don't take to that kindly.
As far as the statement in question, where the author said "light works the
same as heat"--in gum practice, why is that hard for you to comprehend?
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.
I could go on and on with rebuttals but what a waste of my time. But when every thing I have ever posted on gum, save one, has been invalidated, AND even one that was invalidated was then quoted later as being true--Kosar, one has to wonder what the real issue is here. I try valiantly to ignore most of this stuff, turn the other cheek, but enough is enough.
I have learned so much about the gum process from these historical figures
that did it, day in and day out. I can't WAIT to get home and try a bunch
of new things! And I love sharing these tidbits with the list!!! It is so exciting to me, and I'm sorry that you don't feel that way. There is, however, always the delete key, or, as you have mentioned doing in the past (and personally, for the future, it is rude to tell someone they are on your "blocked sender" or "junk mail" list), blocking their posts so they go into your junk file.
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.