Quote Originally Posted by Photo Engineer View Post
Remember that hypo is the best, but decomposes in solution and therefore, your hypo solution should be made up fresh every month and should be kept refrigerated.

I hope this helps.


Hi Ron- I wish I had known you when I was working on the matrix film development. When we had Fotokemika make the film from my formulation, the first trials came out totally fogged (I mean BLACK!). I travelled over to Croatia, and sat with the emulsion chemist, and tried to think of what went wrong. We decided that there was too much hypo being added to sensitize. The amount was about 10 times the normal amount. We proceeded with the regular amount, and everything worked fine. After further scratching my head, I figured out that my hypo solution had slowly gone bad over the 3 year period I was making trial emulsions, and that caused my additions to slowly increase. Stupidly, I hadn't realized that the hypo solution was slowly going bad! It was a major snafu, causing much pain and expense. Experience is so valuable! Other than that problem, the emulsion scaled very well from 4L mixes to 100 L mixes.

Regards - Jim