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

On Tue, 20 Jan 2004, Christina Z. Anderson wrote:
> Blacklow p. 127.
>
> As far as humidity and temp, both increase dark reaction acording to many
> authors--the insolubilizing of gum at a quicker rate, without exposure to
> sun.

Actually this is a perfect quote on several points, illustrating what's
wrong wrong wrong not only about most gum lit, but about alt lit in
general. Note the "according to many authors." Oh, residual matter !
What that obviously means is she doesn't have a clue, CERTAINLY hasn't
tested for herself, and has simply skimmed the usual suspects and copied,
non-commitally. That method of cut and paste technology is rampant,
endemic, and quite deadly in so many of our "bibles." In fact it's THE
primary authority on gum.

(And I also note that Kosar is a fine example of this method, although
possibly through sheer weight of footnotes has been accorded an authority
I have never found in his pages, studded as they are with "probably,"
"possibly," and similar equivocations. I'll add however, that some wicked
evil pro-authoritarian has snuck into my house & stolen that book, because
after high, low & inbetween search, it cannot be found.)

Digression aside, there's also the fact that the meaning of the term "dark
reaction" is, I believe, distorted above. Certainly my understanding of
the term is that it means, once exposed to light, the reaction CONTINUES,
even in the dark. which was why commercial photographers in early days who
exposed a whole production line to sunlight and then developed all
together at the end of the day, changed exposure progressively, giving
less in the first hours to allow for "dark reaction."

If that phrase had been written "without *further* exposure to sun", it
would have been OK, tho the "many authors" part is still a turnoff. I
think anyway as a rule we refer to a coating that has been reduced (or
whatever the chemical reaction) by sitting too long on the paper or other
adverse condition such as heat and/or humidity even without light exposure
as "fogged."

Judy

>
> One thing I always do is check my sources before posting to the alt list, as
> I figure one way or another my head'll hit the proverbial chopping block.
> Hey, maybe I don't explain things well from time to time, but as far as
> research goes, as a used car salesman might say, "trust me." That's my hog
> heaven.
> Chris
>
>
> ----- Original Message -----
> From: "Katharine Thayer" <kthayer@pacifier.com>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Tuesday, January 20, 2004 4:19 AM
> Subject: 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 19:14:08 2004