What are accepted methods for testing for reciprocity failure? Obviously, one wants to consider the deviation from expected exposure for extended exposure times.
I can see where one would want to use a densitometer to measure film density as one increases exposure and look at departure from linearity in some fashion. But, I don't understand the details.
Also, sometimes adjustments in development, as well as adjustments in aperture are recommended. How does one evaluate for both changes in exposure and changes in contrast due to long exposures?
Sometimes adjustments in exposure times are given, instead of adjustments in aperture. How does one determine these adjustments in times?
I'm particular interested in details. Does anyone know good references for testing and for determining corrections for reciprocity failure?