Marilyn <marilyn@xxxxxxxxxxx> writes: > I need your help again, please. > > Here in the southern California desert cold water coming from the > tap is sometimes 85 degrees. This is hot for processing black and > white film and the times/temperatures on the back of the chemical > bottles only go up to the temperature of 75 degrees. Is there a > formula for figuring adjustments for processing film in warmer > water? I can cool water down by adding cold water from a water > cooler, but I need such large amounts of water to process film, that > this becomes difficult. Well, I know how they used to solve this -- I remember seeing darkroom water chillers in catalogs in the 1970s! You'll run into problems with uneven development if the time in the developer gets too short, both because of timing errors being more significant, and because of agitation issues (it's agitated fewer times). You'll also run into problems with the emulsion getting very soft and easy to damage at the higher temperatures. I don't suggest just giving up, though; I'm sure somebody can tell you the shape of the curve, so you can get the time about right at temps off the high end of the chart. Try it on some "scratch" pictures (a "scratch tape" was a reel of magnetic tape that didn't have anything on it that you need to keep, so you could use it to write test data onto) and see how it works. Being aware of the areas where you'll have trouble may help cope with it. Also, for teaching purposes, results not perhaps good enough for professional use may still suffice, particularly if you make it clear to the students why their results are somewhat compromised. -- David Dyer-Bennet, <mailto:dd-b@xxxxxxxx>, <http://www.dd-b.net/dd-b/> RKBA: <http://noguns-nomoney.com/> <http://www.dd-b.net/carry/> Pics: <http://dd-b.lighthunters.net/> <http://www.dd-b.net/dd-b/SnapshotAlbum/> Dragaera/Steven Brust: <http://dragaera.info/> Much of which is still down
