What is the best way to regulate the temperature of developer and fixer whilst tray developing prints?

  • 1
    \$\begingroup\$ you could use a suos-vide immersion heater/circulator to main temp quite precisely, but I don't know if they can maintain such a low temp. \$\endgroup\$
    – dandavis
    Sep 29, 2023 at 20:33

1 Answer 1


Black & White materials are usually processed in fluids that center on 20°C (68°F). This was considered “typical” room temperature in Europe. Most color films and papers are designed to operate at a much higher temperature. The best method to adjust and hold the temperature of the fluids of the process is the water bath”. This can be an inexpensive plastic tray. The bottled fluids of the process are placed in this tray, half submerged. The temperature of the surrounding water bath is adjusted as needed to bring the bottled fluids to the correct temperature. Once the correct temperature is reached, we monitor it with an accurate thermometer.

On the web, you can find and purchase laboratory equipment designed to set and keep the water bath at the desired temperature. However, such devices are generally not needed. All that is necessity is to pre-prepare all the fluids that will be used and pour then into trays and then process the films or papers soon after.

If laboratory accuracy is required, you can invest in a circulating tempering system. These are expensive devices that both heat and cool controlled by a thermostat.

  • \$\begingroup\$ Much appreciated. Now I’m wondering how to find a water bath or tray large enough to accommodate the paper developing trays if that is necessary. \$\endgroup\$
    – Solomon
    Oct 1, 2023 at 18:23
  • \$\begingroup\$ Maintaining the working trays at temperatures via a water bath is not necessary. An exception is sensitometry work in the laboratory, We develop print papers by inspection under safe light. This negates the need for super precise developing. \$\endgroup\$ Oct 2, 2023 at 14:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.