U of S | Mailing List Archive | alt-photo-process-l | Vandyke Question

Vandyke Question

Good day List,
I recently decided to print some images in vandyke and found a 2 year old bottle of sensitizer hidden on the shelf. Thinking it was too old to use, I mixed up a new batch only to find that when I added part c the sensitizer turned cloudy and eventually separated with a clear liquid on top and a grayish tan sludge on the bottom. I tried making a second batch thinking I added part c too fast but I got the same result. I thought the water I distilled might have been contaminated so I tried again with store bought distilled water and it happened again. Frustrated, I ordered all new chemicals from Artcraft and tried again today - same result. If I let the sensitizer sit for 24 hours then filter it I get a clear liquid which lacks contrast and is rather thin density wise. Anybody know what's going on here?
My formula is:
Part A
9 gm - Ferric Ammonium Citrate
33 ml - distilled water
Part B
1.5 gm - Tartaric Acid
33 ml - distilled water
Part C
3.8 gm - Silver Nitrate
33 ml - distilled water
Mix parts a, b, & c separately. Add part b to part a slowly with constant stirring. Add part C very slowly with constant stirring.
Any help would be greatly appreciated.
Best to all - Scott