Film Reciprocity Failure Compensation Factors For Films

[Alan Klein]

I have both Reciprocity and Exposure Assistant on my Android phone. Exposure compensation & times are similar when you compare them using the same film and metered time. Experimenting is essential, but having these as starting points helps.

What app?

[Doremus Scudder]

Here's Howard Bond's article. https://www.willwilson.com/articles/...ciprocity2.pdf

Some of the results are likely outdated, but methodology, etc. are still valid.

You can use these as starting times for Kodak materials (I find they are close with TMY and 320Tri-X out to 20+ minutes).

For Ilford, use the data that Michael R links to and make yourself a chart.

Best,

Doremus