Yes, I'm still astounded at how much Henry did!

I see in Haist that the discussion of this paper (Altman-Henn)starts on about page 415. Haist gives the pertinent tables: the exact developer formulations as well as the results. It seems like most of the significant results are there, so I'm wondering what Michael's questions would be.

Q. First question might be, why do the formulas vary, beyond what is the aim of testing? For example, in the first formula set, they intend to vary only (sodium) sulfite, at 10,30,100, and 200 g/l. Yet they also vary bisulfite and Kodalk.

A. They say that the base formula, AH-3, is essentially D-25. Since different amounts of sulfite would change the solution pH, and activity, the adjustments were made in the interests of "maintenance of approximately constant activity..."

Q. Next question might be, how were the different developing times determined, and why do the resulting gammas vary?

A. They say, after the formulas were decided on, "complete time-gamma studies were made, and times of development at 68 deg F for a gamma of 0.65 for all emulsion-developer combinations were chosen."

My best guess is that, even though the final result (gamma) varied, they decided to stay with their original plan. Note that the data tables are foot-noted "All data from single runs, except..." sample AH-1 was average(5 runs) and the D-76 (1:1) reference was average(2 runs).

Q. How were the test films processed?

A. The say, "Accutance, granularity, and sensitometric-control strips were then exposed and processed for the times indicated by these studies. Processing was in the sensitometric machine of Jones, Russell, and Beacham, which gives strong and uniform agitation."


I hope this is a good start as I probably won't be around when questions start.