RE: gum/dichromate ratios

I have to agree with Chris here - the amm.di.needs to be at about 15% for
digital negs. I found this out by a lot of experimentation......
I also mix my gum "as needed" rather than keeping a bottle full, that way if
I can't get back to printing for a while, I'm not throwing old gum out, or
using toxic preservatives. I'm very aware that I'm exposing myself to toxic
chemistry all the time, even with the precautions I take. You might say I'm
paranoid about it :)
Kate

-----Original Message-----
From: Christina Z. Anderson [mailto:zphoto@montana.net]
Sent: Friday, 11 November 2005 3:19 a.m.
To: alt-photo-process-l@sask.usask.ca
Subject: Re: gum/dichromate ratios

I use I part gum powder to either 1 or 2 parts water, weight to volume, and
then use my gum/pigmnet to dichromate as 1:1, but the dichromate part of the

equation is either 1/2 water 1/2 saturated dichromate or 3/4 water 1/4
saturated dichromate. In other words, I only use a 15% or 7.5% dichromate
solution in my mix.

Lately i switched to the 15% as I'm testing my new curves and colorized negs

and such, just because the layer is very stable and if I want to let it
automatically develop (e.g. sit face down in water) the color falls off just

fine, or if I want to spray develop it holds up to spray perfectly. But I
don't use saturated dichromate 1:1 any more since switching to
diginegs.
Chris
>I use 1 part of saturated dichromate to 2 or 3 parts of gum/pigment
>mixture. My gum is commercial 14 baume. Less toxic and expensive chemicals

>(ammonium dichromate) the better. As you can see the ratios are flexible
>and you will do best finding your own workflow.
> Marek M
> Houston
>
>

-- 
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.362 / Virus Database: 267.12.8/163 - Release Date: 8/11/2005
 
-- 
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.362 / Virus Database: 267.12.8/166 - Release Date: 10/11/2005