Re: gum bichromate

anthony corkhill (corvet@corvet.win-uk.net)
Fri, 09 Jun 1995 22:46:23



>> I used this process about 12 months ago using saturated potassium bichromate &
>> 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 because my
>> bichromate solution is old? If any one who has experience of using this
>> process could give help or advice on the best and most consistant methods of
>> 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
Carson Graves

Thanks for this. Certainly the image doesn't develop. If it were a
conventional silver print it would be grossly over exposed ie black! How do you
measure & if necessary control humidity? This is not something I've had to
bother about before with silver printing! I've found de-humidifiers for sale
at about 200 UK cannot really justify spending this amount of money!