• FX-15 is indeed an interesting formula. I'll have to try it sometime. It's good that we can ask one another about recommended development times, but notice that there can be a 2:1 disparity in the recommendations. OK - it's a starting point. When you don't have a clue about times, remember that once the shadows are fully developed, you are just adding contrast with further development. Your task is to find the time that gives the right contrast. Short rolls of 35mm film are great friends at times like these. As a first guess, look for a similar developer for which you do have times (or use the recommendation you got from someone). Add 10 percent if you are uncertain. Expose a short roll to a scene with a full range of values (maybe a step tablet) and develop for your guess time. Bracket. Evaluate the contrast (best if you can compare it to something you know is right). Adjust the time accordingly. Repeat as necessary.

When you have the times for one film down cold, can you extrapolate for other films? Maybe. Once again, look at a similar formula for which you have times. Adjust your time proportionally for the new film, and try a roll. Evaluate the contrast and adjust accordingly. For example, say you determined the development time of HP5 to be 22 minutes in FX-15 and 13 minutes in D-76 (1+1) (a sort-of similar developer). You want to develop Tri-X. Tri-X develops in 9.5 minutes in D-76. So FX-15 takes about 1.7 times as long as D-76 (1+1). Try 16.5 minutes for Tri-X in FX-15 and evaluate the results. The trouble is, this does not always work, so be prepared for poor results on your first roll.