Alan Johnson was kind enough to mail me the negatives from his D316 longevity tests. He used D316 that was 2 months old and 12 months old. As he said, he was rough on the developer, storing it in a 90%-empty bottle at room-temperature, and opening it for a half-hour each month. So that was a worst-case test, resulting in dark orange concentrate. I measured the neg's on the densitometer, and I calculate that 30% more dev-time was needed. From this, you can estimate how much to increase time for various shades of colouration. Here are the time-increases that I would estimate:

clear -------------> 0%
yellow -----------> 7%
dark yellow -----> 15%
orange ----------> 22%
dark orange ----> 30%

I suspect these numbers are good for 214D and similar, not just D316. Also, I suggest freezing the concentrate in storage: Hopefully it will stay clear for a year, and you'll never need to increase the dev-time.

Mark Overton