B&W Photo Development Water Temperature Equipment

[Dave Colangelo]

Ive been running a bunch of rolls recently and focusing on temp (for no apparent reason) heres what I have found. For the record I am using a Paterson System 4 tank that holds 1 120 spool or 2 35mm spools. The thing to consider is the ambient room temperature.

In the colder months I have no problem keeping my apartment at 68 Degrees and thus just processing at room temp. I use distilled water so I let the gallon jugs sit for a while before processing always on the mark.

The bigger issue is in the warmer months in which case I need to cool the developer down a bit. Ambient temp is anywhere from 74-78 degrees depending on when I get home and turn my AC on. I mix up the dev in the measuring cup and then sit it in an ice bath to cool down to 68. Stir frequently to ensure even cooling. Once at 68 dump in and begin processing. Frankly for the ~10 minute process time I have not seen huge temperature rises on the last 4 rolls I did yesterday. Water has a fairly high specific heat and will hold temp well over a short time span. The paterson tank allows you to insert a thermometer so I keep an eye on it in between agitations and submerge in the ice bath if the temperature is rising too much.

If you are using ilford film and developers they provide very accurate correction charts for processing at a range of temperatures. I have used these with great success. You can find it all on their website but you will need to download the data sheets for the individual film stocks.