Re: gum bichromate
Virginia Boehm (firstname.lastname@example.org)
Fri, 9 Jun 1995 14:16:31 -0700
>> I used this process about 12 months ago using saturated potassium
>> gum based glue. It worked though not very consistantly. Unfotunately
I did not
>> follow this up until now when it doesn't work at all! Is this
>> bichromate solution is old? If any one who has experience of using
>> process could give help or advice on the best and most consistant
>> gum bichromate printing it would be most appreciated
>> thanks, Anthony
>It's hard to offer specific advice without more information, but one
>thing to watch out for is humidity. If there is too much, the image
>won't "develop" (wash out). Generally, the lower the better, but
>best is a constant relative humidity level somewhere below 50%.
>I haven't heard of a dichromate solution getting too old to use.
>Hope this helps
Never found the age of the dichromate saturated solution to be a
problem either. I wonder if the problem is humidity when it doesn't
develop properly - after all you develop the stuff in water, which is
about as humid as it gets. When it doesn't come out and the image is
loss the villian sounds like overexposure to me. The gum all hardens
as the light penetrates even the dark areas of the negative.e
If you are using the sun as a light source (and I do) this time of year
I avoid exposing prints between about 11am and 2pm. The exposure
times are in seconds and you have to hover over the print, ready to
snatch it at whats hopefully the right moment.
If you are using the sun, try morning and late pm.