To Mick and Gbroadbridge, here are some hints.
Papers contain high chloride emulsions. As such, they are senstive to chlorine and other halides and some chemicals used in water treatment. However, the manufacturers know that and engineer their papers (or should) to avoid that very problem. I have never observed that problem with any variant of Kodak papers. I have never heard of it with Fuji papers. Agfa papers have been such a small runner that I am not familiar with their response.
I use a pre-wet all the time.
Early instructions from Kodak and Jobo among others recommended a prewet. I have found that I get uniformity problems in both paper and film without one, and sometimes get variable results along with air bells due to bubbles. So, I find it a plus.
Now, as for cyan streaks. I have found that the most usual cause of cyan streaks is due to insufficient stop action after developing RA paper, particularly at high temperatures. If I use a stop, I never get the streaks, but if I omit it, I get streaks. This is due to fixation and development taking place side-by-side at the same time in that hot drum.
Here is my process:
Prewet 100 F 45"
Develop RA-RT Repl 45" - 1' Depending
My C41 process is the EK process with two 30" 100F prewet stages.
Thank you for the nice comment. I try to help here as much as possible drawing on my experience in product and emulsion development work at EK.
My warmest regards to everyone who has shown an interest in this. Please feel free to contact me personally with questions. Some people seem to feel reluctant. I really don't mind at all. I keep busy on these cold rainy (soon to be very snowy) Rochester days answering mail and chatting or working in the DR.