Last year I used Patterson's RA-4 printmaster and Blix to try out colour darkroom work. I was no great shakes at it but did enjoy it. I know it's probably not cost effective and scan and print is good enough for my colour work but I'd really like to play again.
Since the demise of printmaster does anyone have any suggestions as to a cheapway to do RA4 for the occasional user without having to buy expensive new developer and blix every time I come to do a set of prints (once a month would be more than enough).
If the stuff you buy lets you mix in small amounts the concentrates will keep quite a while.
Blix even diluted lasts quite awhile. It's developer that goes bad quicker. But I find in a full bottle developer has a reasonable lifespan.
Now I use drums which let me mix fairly small amounts. I also use a prewash. The prewash keeps the paper from sucking up developer so the developer bottle is always full. I found that when I wasn't doing a prewash the developer would go off quicker. My thinking is the ever growing headspace in the bottle caused problems.
If the prewash was causing problems wouldn't I be seeing shifts in the filter pack? I re-program every so often and the changes are very small. I always put the fractional changes down to developer aging.
There would probably be a contrast loss and hue shift both. The quantity may or may not be important to you. It is to me. I do not reprogram.
Demostrate it to yourself by diluting some developer with water. If you use 60 - 120 ml of developer, it would not be unreasonable for 25 ml of prerinse water to remain in the tube. Make a print, then add 25 ml of water to the developer and try to make a duplicate. This would probably be the result of one run or maybe 2.
I run the solutions into a beaker and measure them. A suprising amount of carryover takes place in tubes. That is why Kodak suggests you use a stop bath when processing with tubes, due to carryover of developer into the blix.
If you use a stop bath, it will turn bright pink very quickly due to the carryover and oxidation of developer. And, the stop will remain nearly constant in volume due to carry in of developer and carryout of stop into blix.
I don't know about contrast but the analyzer tracks colour and paper speed. I reprogram at half the estimated developer life and the changes are very small. I'd have to pull my notebook out to say for sure but I'm not underestimating how small the changes are.
When I wasn't prewashing the changes would be much larger and quicker. The developer would die fairly quickly. I mean total developer failure.
I have found that RA-4 chemicals keep quite a long time (months) if refrigerated. If you use trays there is no prewash problem. You will, however, have to dial in the time for the developer.