RA-4 Temp. Control Tips?

If you are unable to heat your 55 degree darkroom then drums used one-shot would be less problematic than trying to heat trays. But I would not process at 35 C, but instead use FRESH Kodak RA-RT developer/replenisher at 68-75 F for two minutes. It works very well at these temperature and it would be far easier to heat your chems to, and maintain, than 35 C. At these temperatures, a given change would have far less effect on color balance than at a high temperature. In your environment, you can bet on a quick temperature drop in the drum with high temperature development.

I just bought a temperature control mixing valve for big bucks (for me) because I am going to try color work again. It is a used high quality Leedal. I haven't tried color since the early 80's. Back then I used drums and baths trying to control the 100 deg temp by manually mixing. I got good results, but what a pain. I dreamed of a mixing valve back then, and this is an old dream fulfilled!

In drums I use RA/RT at 83F for 2 min. This seems typical. For rotary processing you ordinarily need different timing than in trays.