Van Dyke

I have just resubscribed to this list after an absence of three years. Similarly, Ihave restarted my interest in alt photo processes. I would like to seek advice on a problem I have mixing Van-Dyke sensitiser. Three years or so ago I successfully mixed a batch of Van Dyke sensitiser. It is still usable but is almost used up. I tried, three times, to mix another batch but on each occasion I end up with a bottle 3/4 full of sludge. The formula I use is : solution A = 10grams ferric ammonium citrate (green) + 35ml of deionised water; solutionB = 1.5grams tartaric acid + 35 ml deionised water; solutionC = 4grams silver nitrate + 35 ml deionised water. When all chemicals are dissolved I add B to A, stirring and then very slowly ( a drop at a time) add C stirring continuously.

Can any one advise me what I am doing wrong and is there any way I can reclaim the 'sludge'

Thanks

Bob Redman, UK
Received on Tue Apr 12 13:06:53 2005