Re: Gum dichromate issue

From: [email protected]
Date: 08/09/04-10:23:59 PM Z
Message-id: <>

Thanks Etienne,
No, I do not have problems with the registragion and I print on 16x20 canvas
size pictures of 14x11, I size the paper and I am on the limit of problems.
I do my threee negatives with Photoshop and I print full color confortably,
I am trying to learn and read more to avoid possible mistakes.
Most of my errors come from specific pictures so the proper negative is an
issue, sometimes I change the curve factor (on photoshop which is the
contrast in a conventional film) on the Red negative but again I am
guessing. Why? I read somewhere that it was the most important of the three
negatives. Why? Is the first I use to print, then I go with the Blue (Yellow
pigment) and I start guessing the solar exposure time and finally I do a
third guess with the magenta pigment to "see" the picture.
The other issue is the pigment, remember "pure colors" do not exist, how
should this be dealt or handle in reality?

----- Original Message -----
To: <>
Sent: Monday, August 09, 2004 8:40 PM
Subject: Re: Gum dichromate issue

> Giovanni wrote:
> > I do have several questions and probably too many but the first is:
> > Is there any book you recommend me to read that deals with the three
> > negatives instead of the Kodak single color negative?
> Good question. The best books on separation practice I recall were short
> things put out by Kodak that were out of print long ago. I'll look
> my photo books and see what I can find. First, you have to separate the
> colors. Are you intending to make three in-camera negatives, or shoot
> color film (or digital) and do the separation later?
> The basic issues are (i) getting the color balance right, which is a
> of using the right filters and choosing the right exposure and development
> for the three negatives [with DT, one often develops the 3 negs to
> different contrast levels -- I suspect the same may be true of other
> processes]; and (ii) registration of the three [or four, with a luminance
> layer] negatives. In the old days, we punched holes in unexposed film and
> used pin-registered film holders, enlarger negative holders, and printing
> frames throughout the process. Condit, the manufacturer of
> pin-registration equipment, went out of business a few years ago. I
> understand that shrinkage is a factor with multi-layer gum, so
> may be more of an issue for you than it is for DT printers.
> Best regards,
> etienne
Received on Mon Aug 9 22:26:18 2004

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