I wonder if this is correct. My understanding is that a
difference of about 30% in development time will result in about
a one paper grade difference in contrast for cubic grain films
while only a 20% change will do it for tabular grain films.
Perhaps 15 seconds means 15%, which makes more sense. That would
mean T-grain films have about twice the rate of change of
contrast as cubic grain films. That would explain why they are
much fussier than conventional films.
BTW, I found my copy of "Photographic Chemicals and
Solutions" by Crabtree and Mathews (1938) while going through
some storage. Probably outdated in many ways but has some
interesting stuff buried away in it.
Does anyone know what Nepera Solution was? A non staining
developer. I have a vague memory of finding a formula for it long
ago but no longer remember what made it special. It is mentioned
as an alternative to Amidol for redeveloping prints after stain
removal but in another section D-72 (nearly Dektol) is given as
an alternative. Takes some careful reading because there is other
stuff hidden away. I had totally forgotten I had this book.
On 11/12/2019 1:33 PM, Robert Shanebrook (Redacted sender
makingkodakfilm for DMARC) wrote:
WB6KBL
Use time-and-temperature to control contrast/density. Yes, T-Max Films are more sensitive to time-and-temperature differences than 3D films. T-Max Film development time differences of +/- 15 seconds are enough to make a difference. For 3Ds 25% is an appropriate difference.
