I have a few boxes of C-41RA developer replenisher with Part C being too old and gone bad. That's a couple of hundred liters of developer gone bad. Recently I went ahead to mix 10 liters of it without part C. I also mixed the right amount of starter to it so it is a complete stock developer without part C. I took ome liter of this developer and added 5 grams of CD-4. The CD-4 powder is something that is ay least 25 years old that I bought in the 80'.
I used this one liter developer and developed quite a few Kodak Ektar 100, Portra VC, Fuji NPS and even a few rolls of Kodak VPS-3 and a roll of Pro100. All were 220 except the Ektar that was a 120. I developed the Ektar first and it was the very best negative I ever produced. I proceeded to reuse the developer and see at which point it would crap out on me. I think I developed a total of 10 rolls of 220 and a roll of 120 (Ektar). I was very surprised that the colors were all acceptable with no obvious color crossover that makes scanning difficult.
The first 4 rolls I developed at 3 min 15 sec standard time at 100 degree F. The rest I extended the time to 3 min 30 sec. I used 470 ml each time for 2 rolls of 220. My processor is a Jobo ATL-2300.
So what I am getting at is old CD-4 powder does last 25 years long or longer. I kept it in a plastic bottle all these years and it looks grey today. But it works great still. Now I am on a quest to buy 500 grams or 1 kg. Where can I get it at a good price?
If you have part C gone bad from your C-41 developer don't throw it away.