van dyke sensitizer help
so - there i was mixing up a batch of van dyke sensitizer for the first time. everything was going fine. i was well warned of adding the silver nitrate to the ferric ammonium/citrate tartaric acid solution very slowly. drop by drop with constant stirring. i checked the mix when i had droped about 50ml of the silver nitrate into the ammonium/citrate tartaric acid solution. everything look fine - then some where about the 25ml mark i checked the solution again and noticed it was a lighter shade of green. i stopped stirring to let the mixture settle and noticed the parcipitate in the bottem of the beaker. i had been dripping the silver nitrate into the ammonium/citrate tartaric acid solution for at least 45minutes. where did i go wrong?
BTW - i was mixing under very low lighting in my darkroom. room and water temp was around 68f and i used distilled water to mix all the chemicals.
I've had this happen many times and it was discussed a bit on the alt process mailing list a few months ago. You aren't alone. Make sure to add all of the silver nitrate then put the solution in a brown bottle let it settle for a few days. There will be some precipitate on the bottom but the solution on top will clear and, provided that the proportions are correct, it should work just fine. Some people filter out the precipitate but I leave it in the bottle and discard it when I reach the bottom. I've found that a lot of the excess silver will go into solution as the mixture ages.
thanks slewis :-) i feel a lot better about mixing another batch.