Rork- What Slynk said above was absolutely correct. I used to develope in a basement, and the temperature never changed more than a few degrees all year. Get the chemicals to stabilize at a temperature, and then adjust the development time according to the directions that come with the film/developer. It may vary by a half minute or so. The other chemicals are not that critical; just should be at same temperature to not "shock" the emulsion. Most difficult, maybe, is holding the wash water within a few degrees. I built a thingy with a big jug and a thermometer to let the hot&cold mix slower. This meant I did not need to watch it so close while washing. [If you do change temperature drastically, like plundging in in ice water, an effect called "reticulation" occurrs. It is kind of neat, but rather permanent!] Jordy- I have to apologise for making such a short comment about your trying color film in B&W chemicals. I know the topic came up before, and you explained why you are trying to do this. [I tried it once myself, as a matter of fact, a looong time ago.] It does work, but you really can't keep much control over it. You would have much less frustration if you practiced on B&W materials, avoiding the C41 stuff while learning to develope yourself.