Re: A little gum test

On Tue, 16 Dec 2003, Kate Mahoney wrote:
> > > Hi Mark, Less contrast with the saturated solution was
> > > postulated....so I'thought I'd give it a whirl. I have been getting
> > > rather flat prints so this is good news. The results (to me) show some
> > > of the reason why I've been having some trouble with this technique -
> > > obviously too much amm.di. I think the reason why the tones are better
> > > is that mostly I've just been overexposing with the amm. di. at the
> > > more concentrated level...

I still think you need to factor in at least 3 defining variables, or make
that 4. One that's omitted here is the viscosity of the emulsion and its
twin, development time. My finding was that using a larger proportion of
water to gum (that is, using more of a dilute dichromate solution that
made the emulsion thinner, or less viscid) and exposing longer made a
*harder* print that could stand more development time and thus give a
longer scale. The highlights held while the shadows peeled back.

In what have become the usual protocols of gum, the highlights -- in soft
viscid emulsion -- would have washed off. The belief has been (fostered
perhaps by someone whose name I dare not mention, tho initials are PA)
that gum will stain if not adequately gum arabicked. I found this not to
be so if the paper is gelatin sized.

PS. Is that how you spell viscid? But it's pronounced "viss kid," isn't
it?

J.
Received on Mon Dec 15 14:29:04 2003