Re: Gum image has reversed

Am I assuming wrongly, Bruce, that you are using lamp black tube watercolor
pigment? Or are you, in fact, using powdered pigments as Dave does?
Because lamp black watercolor pigment is not that big a deal in a half gram
amount--less than a one inch worm, and well within reason of his
proportions. In powder it would be a huge amount--by my calcs a half gram
of powdered black is about 6/10 tsp powder. Enquiring minds want to
know...
Chris
----- Original Message -----
From: "Dave Rose" <cactuscowboy@bresnan.net>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Monday, January 09, 2006 7:30 PM
Subject: Re: Gum image has reversed

> Way too much pigment IMO. I'm using 1gram carbon black per 100ml of gum.
> At that concentration it's very strong. I'm surprised you're getting any
> kind of image.
>
> 30 minutes for development is about right.
>
> Dave in Wyoming
>
> (snip)
>> > >>> Emulsion made from 2.5 ml gum, 2.5 ml potassium dichromate
>> > >>> solution and about 0.5 gm Daniel Smith Lamp Black pigment
>> > >>> Still development for about 10 minutes brought up reasonable
>> > >>> density -- my fear in letting in go on much longer was that I'd
>> > >>> loose the entire image (just like the first dozen or so failures).
>
>
>
Received on Tue Jan 10 01:33:44 2006