Re: Dark reaction in dichromated colloids

Katharine said, huge snip by me: Christina, as I recall, found that she
could store her
> dried coated papers in Montana for days (weeks?) without any dark
> reaction.
>And again, large snip by me: I think the difference between mine and
Chris's Montana experience is
> the humidity, but I don't know if humidity plays a part in these other
> cases where no dark reaction was observed, and it would be interesting
> to find out if Chris sees a dark reaction in her more humid
> environments.
> Kosar recommends raising the pH to 9 to keep the dark reaction from
> happening; he says you can store your papers indefinitely if you keep
> them basic. Since at pH 8 or higher, the dichromate exists almost
> entire>
Katharine,
     Ha! Conflicting in science? How about the conflicts on this in 63
(and counting) sources on gum? Some would say that paper would keep for
several months, some would store in calcium tubes to keep dry, but most
authors do acknowledge dark reaction and that absolute dryness is necessary
for preserving the paper. But several months???
     You are absolutely right about dark reaction and humidity. In MT my
darkroom was in the basement of the house(a half basement, not a deep
one)--no windows, dark, cool, and dry, dry, dry. I could keep paper 6 days
I think, and it'd still work fine, albeit a bit darker orange. I cannot do
that in either MN or SC, but considering dark reaction is affected by heat,
humidity, and pH, MN and SC are out for the former two.
Chris
Received on Sat Jun 12 09:19:55 2004