Re: Roller for gum (was: Re: humidity in your darkroom........

Christina Z. Anderson wrote:
>
>
> A couple authors in books said they didn't print in the summer because their
> prints were "muddy" which I presume to mean either lower contrast, or
> perhaps a higher incidence of staining possible, even, because of the
> increased receptivity of the paper to more moisture (Livick being one).

I was going to comment on this but decided first to go back and read it
in the original source. I've looked through Livick's "book," both the
published pamphlet and the manual he used for his online class (which he
sent me a copy of) and can't seem to find where Livick said this in
either one. Do you have a page number?

It seems unlikely to me that Livick would say that he doesn't print in
the summer, since he's a full time gum printer and prints in a
climate-controlled lab. At any rate, I couldn't find any in Livick
either in reference to not printing in the summer or to dampness
causing lower contrast or staining. But I've probably just missed it
somehow, so if you could give the page that would be helpful.

>Blacklow says don't print in high humidity because the dichromate
> soaks up moisture from the air and become less sensitive--either that is her
> conjecture or she got it from someone else.

Again, I can't find this in Blacklow. I didn't study the whole book but
I did go over the gum chaper quite thoroughly, and can't seem to see it.

I did find the citations about the dark reaction from Crawford and
Livick, but I see the dark reaction as a different issue than
humidity. Livick deliberately keeps the humidity fairly low in his lab
(but perhaps not as low as the air in Montana) so it seems unlikely that
it's humidity that's causing the dark reaction that he's describing
here:

> Livick also says in his book to dry emulsion for 1/2 hour to 45 min, no
> longer, or emulsion will start to set in the paper and highlights will be
> muddy.

Since I print in fairly high RH (85 to 100%) most of the year, but cool,
(here, both unusual cold, like below 20 F, and unusual heat, like over
85 F, are drier than the usual cool damp weather, because they both come
on an east wind rather than from the ocean) and have no problem with
staining, either pigment or dichromate, or other artifacts such as
attenuated DMax, I'm inclined to believe that where people have seen
these effects with heat/humidity, "it's not the humidity, it's the
heat."
Katharine
Received on Tue Jan 20 11:15:28 2004