When to throw out developer?

[Ed Richards]

I am curious - what is the effect on your negatives when developer starts to go bad? For example, I keep Xtol in a tank with a floating lid and a stopcock at the bottom. I draw it down to dilute 1:3 and throw out it out after processing. I use an expert drum and do not do a lot of sheets, so it may take me 3 or 4 months to go through a batch. I still get crisp, full range negatives at the end - assuming the exposure is correct - but is there something else that I might be losing?

[Henry Ambrose]

One of Xtol's properties is that it is consistent over a long keeping time. I keep Xtol in glass bottles (full to the top). When I was experimenting with other developers I kept some Xtol this way for about a year. Upon using the last bottle of that batch I was still getting the same great results. Your floating lid tank should keep it real well for 3-4 months. I doubt you are losing anything.

[Donald Qualls]

Of course, one of XTOL's other properties is that you can't tell when it has failed, except you get extremely thin or blank film. The stock solution doesn't change in any visible way when it fails, it simply fails.

Recommendation: test your stock solution with unimportant, correctly exposed films before committing important images. Best to do this even with freshly mixed developer, for that matter; packaging damage could result in "expiration in package" (also known to have occurred with XTOL in the past, though apparently corrected by Kodak a year or two ago), and a mixing error, water impurity, etc. could cause a developer to have unexpected variations in activity.

However, if the developer still works and your film speed or contrast aren't changing, there's most likely no reason for concern -- weakening developer will result in loss of film speed or reduced contrast.