Kodak RA4 Ektacolor Concentrate Life

FYI: I had unopened Kodak Ektacolor RA Developer Replenisher RT to make 10 liters (Parts A and B), and Kodak RA Bleach Fix to make 10 liters (Parts A and B), with expiration dates of November 2018. I couldn't get to using them until last month but I have been making prints and they are just fine (as evidenced by being able to use the same color filtration and exposure times as in the past). Glad that they are still effective so long after the expiration date. Since opening the concentrates I made up all of the developer and store them in full 1 liter PET bottles, and make up liters of blix as needed, and store the unused concentrates in smaller, full PET bottles; I assume this practice has helped keep the chemicals effective.

I personally prefer to proportionately mix only enough chemistry for a given daily session. PET bottles vary in quality. Some of those sold in camera stores are quite thin and allow oxygen to penetrate. Then there are serious lab grade ones. You want them full, or else use an inert gas to displace air. Developer has A,B,and C components, with the lesser quantity B being by far the worst in terms of dicey storage life. I really don't know how long the full unopened,unmixed concentrates last. Perhaps two or three years after manufacture, depending. But I really don't trust mixed developer for more than a few days, and even that long would worry me with respect to the best possible results.

Correction, developer has Parts A, B, C.

Have had no problems making up all 10 liters of developer at once, stored in 1 liter PET bottles, but I will end up using it all in 6 weeks. Bleach fix is made up 1 liter at a time and is all used either the same day or the next day.

I'd rather be safe than sorry with respect to storage life. I learned that the hard way. When frustration, and loss of time and money are involved, one doesn't forget the lesson so easily.