Eggshell, Then I would definitely recommend that you let the paper sit, in a non UV part of your darkroom/coating area, for 30 minutes before printing. You can help the paper retain more moisture during exposer by using saran wrap or similar product behind your paper between it and the felt. You should also see a speed gain in that palladium is FASTER at higher humidity levels. So don't expect it to print at the same speed. You can additionally humidify after exposure, but I have never measured the effect, but you will see additional print out. If this is your standard printing technique, you will see across the board shift in color on ALL papers.
Originally Posted by eggshell
If you want to try the ZIA approach, get a room humidifier and steam your paper. Since I started rehumidifing my coated paper, I have used a humidifing box with a fan and a rheostat control wicking system. I prefer the evenness of a chamber as a opposed to the ramdomness of moving the paper evenly over a moisture stream. It also frees one up to do other procedures in the coating exposure work flow.
Thinner papers can use less time, but I like 30 minutes to allow for a little back and forth in the moisture flow as the paper stabilize to your desired rH.