The subject line sums up the question. I mixed up a gallon Kodak Ektacolor RA kit about a week ago and when I used the last bit of it yesterday, the developer was quite a bit darker out of the bottle and the white borders of the prints were definitely "dingy." I assume this is an oxidation effect? If so, is it primarily oxidation of the developer or the bleach that's causing it? Other than the above problem, I have to say my first RA-4 printing experience has been pretty painless. It took a couple sessions to get a handle on filtration, but once I realized the one wheel was the "Christmas Wheel" (green/red) and the other the "Easter Wheel" (blue/yellow) I was in business. By yesterday's session I could pretty much settle on the right filter pack with 3 test strips.