Last night I sketched out an idea for a coating block for coating emulsion on film base. I'd like to test out the idea and would like to know if there is a (hopefully common) material that I could add to the gelatin (KNOX at this point just to try) to stand in for the AgX? Or, does the addition of the AgX not substantially change the behavior of the gelatin? I don't care to waste expensive silver nitrate until I have some idea if this idea will even work! Also, is a chrome alum hardener necessary to add to the emulsion just prior to coating? Or, are there other hardeners to use? I tried a really rough version of my idea to coat some gelatin on some acetate base on a piece of glass last evening and it was still quite sticky (although it seemed hard) this morning after about 9 hours. Would a hardener help this or is sticky emulsion an indicator of a different problem or it is just not dry yet? The coating thickness should have been in the range of 8 - 10 mils. But again, this was a very, very rough test and I am looking for some ideas. Thanks!