All films shot at rated ASA/ISO speeds.

For Arista Edu 100 -- I suggest 14 minutes with 15 sec. agitation per min.

For Artista Edu 400 and Ilford Pan F 50-- I suggest 12 minutes with 15 sec. agitation per min.

Kodak TMax 400 -- not recommended

The effects of extended development depend heavily upon the stock, but tend to work best on slower, old-style emulsions.