Time, Temperature and Agitation By John Kasinger
Time temperature and agitation are the three factors that determine the quality of film development. Oh sure, there are more like water quality and the like but they are the big three and they are all interwoven. This is for the developer.
Time: To a large degree this determines the contrast and density of the negative. Too much time and the image is too contrasty and dense. Too little time and the image is flat and lacks density.
Temperature: 68 F (20 C ) is the normal temperature for most darkroom work and is what I use all of the time. This also affects contrast and density but in a different and unpleasant way. Too hot, too contrasty. Too cold and the results are flat and thin. Thin in the film world means not much image.
The big thing about temperature is keeping it accurate and consistent through the whole developing process. A very good darkroom thermometer is a must. The chemicals and water should not vary more than 1 degree. The biggest single factor of beautiful, smooth and tight grain is temperature control.
Agitation: The roll film tanks that I show here require hand agitation. Good agitation gives even development with no blotchiness. I use 3 inversions when the developer is all in the tank and 2 per minute for the remaining time.
Proper exposure is required for a great negative.