In August, I bought the Kodak Ektacolor RA developer and blix concentrates from B&H: http://www.bhphotovideo.com/c/produ...15580_Ektacolor_RA_Developer_Replenisher.html http://www.bhphotovideo.com/c/product/28779-REG/Kodak_8309031_Ektacolor_RA_Bleach_Fix.html This is enough to make ten liters of each chemical -- a big initial investment for a first-timer, but it seemed to be the most cost effective and fuss free way to get into RA-4. For the developer,I plan to prepare the ten liters of working solution at once and keep in twenty 500ml PET water bottles filled to the top. I'll probably use about one bottle per session, and I can keep the bottles in the dark -- in room temperature or the fridge. It's the blix that I'm unsure about. Is it as sensitive to oxidation as the developer? Also I've read that the bleach and fix don't play well together over long periods, and that it might be best to prepare smaller amounts (two liters) as needed. Any thoughts on this? If I prepare smaller amounts as needed, how best to keep the concentrates once they've been opened? Thank you.