Re: Back-exposing on plastic (was: Re: Gum transfer

From: Yves Gauvreau ^lt;gauvreau-yves@sympatico.ca>
Date: 04/27/06-01:02:14 PM Z
Message-id: <0e0501c66a2d$18b58660$0100a8c0@BERTHA>

Katharine,

your right about most controls except for multi-exposure, I got carried away
when wrote the list of controls you would lost. Anyway, as you already said
in other words, you have to find the optimum mixture to apply but what I was
thinking and didn't really say is when this optimal mixture is found I doubt
you'll get a linear response from it. By this I mean by printing a step
tablet for example you will most probably not get a constant increase in
(optical) density between each step. Is it necessary to get a linear
response, probably not but that is another story. The suggestion I made is
that by applying a curve to your digi-neg you would be able to enhance
contrast where ever you like, highlights, mid-tones, shadows or anywhere in
between. Hopes that's more clear.

Regards
Yves

----- Original Message -----
From: "Katharine Thayer" <kthayer@pacifier.com>
To: <alt-photo-process-l@usask.ca>
Sent: Thursday, April 27, 2006 2:13 PM
Subject: Re: Back-exposing on plastic (was: Re: Gum transfer

>
> On Apr 27, 2006, at 10:37 AM, Yves Gauvreau wrote:
>
> > Katharine & all,
> >
> > just a thought on making back exposure gum prints maybe the
> > negative as to
> > be fitted with a curve since you have no other control now (multi-
> > exposure,
> > long exp, short exp, pigment load, etc). Maybe this would make a
> > world of
> > difference...
> >
>
> I doubt it; first of all, your premise isn't correct. Of course we
> have the usual controls of pigment load, exposure, dichromate
> concentration; that's what this whole discussion is about, to try to
> determine what might the optimum levels of those variables be in
> combination with each other to produce the kind of tonal scale we're
> trying to achieve with the back-exposure. . As I've demonstrated,
> too much pigment can result in a sooty, grainy, contrasty image even
> when you print from the back. And so forth.
> Katharine
>
Received on Thu Apr 27 13:00:31 2006

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