How dry does a darkroom need to be?Updated 2 days ago

Your darkroom should be kept as dry as possible to ensure consistent results. Ideally, the humidity should stay below 40%, with 20% or lower being even better. Unless you're using an inkjet direct-to-screen system, there is essentially no downside to maintaining very low humidity using a dehumidifier.

A dry environment helps emulsions dry more consistently and reduces the likelihood of exposure and coating issues. If you live in a very humid area, like the southern part of the U.S., you may need to leave the dehumidifier on 24/7. In order to keep it running that long, you will need to connect a drainage hose to the dehumidifier so it does not fill up and stop working.