I have been experimenting with this developer (Kodak RA4 Dev/Repl RT) for over a decade. Listen to me and you will have NO problems with 'black B' sydrome (!).
The most vulnerable component is the 'B', but both the 'A' and 'B' should be oxygen-protected. You do not have to refrigerate ANYTHING except paper and film. Period.
Get yourself some PET plastic bottles (soda, juice, Gatorade). They are clear, brittle plastic and are airtight. (Yes, I get them from the trash and wash thoroughly and let dry completely.) It's tough to find ones that hold less than 300ml but for small quantities use 50ml liquor bottles (with metal cap) or glass bottles with tight fitting caps. (Of course, glass is just as good but the PET plastic is a boon to darkroom use as there is no breakage.) IMPORTANT: you MUST fill to the very rim such that when you invert the bottle only a small bubble appears at the bottom. To take up slack in the larger bottles use standard glass marbles (Walmart). To take up the slack in the liquor bottles use tiny glass marbles (tougher to find, but Arts and Crafts stores have them (in Philadelphia, there is a chain called AC Moore).
The Kodak concentrate quantities for the RA4 dev/repl RT (roller transport) are as follows: 10 liter size: A = 500ml, B = 230ml, C = 500ml. For the 25 gallon size: A = 3784ml x 2 = 7568ml, B = 1422ml x 2 = 2844ml, C = 2370ml x 2. You will notice that there is a slight ratio difference for the 'B' part between the 10 liter size and the 25 gallon size. I do not know why Kodak did this but do the math to figure what you want to extract from each part when you mix partial quantities. Keep the original ratios intact.
If you do what I said here you will be able to keep the concentrates INDEFINITELY. When I need some, I open a bottle and extract only what I need with an eyedropper. I then make certain that there is no airspace by adding the appropriate marbles (medium marbles displace about 2ml and tiny marbles displace about .5ml).
Now, a final caveat: DO NOT UNDER ANY CIRCUMSTANCES use PET plastic for the 'C' component of the RA4 developer! It will eventually eat into the plastic and cause it to weaken and corrupt the container. I learned the hard way! Instead, use either the original container or use glass. I have found that this 'C' part does not have to be protected from oxygen BUT... in time sediment does develop which I filter out. I have found NO PROBLEMS from letting this sediment result and simply filter it out whenever I need some part 'C'. I believe that this 'C' is the highly alkaline component needed for the developer.
Also, you can freely hold mixed (yes, even diluted) developer in these PET plastic bottles as long as you keep them filled COMPLETELY to the rim. When mixed, you do not have to worry about the 'C' part doing damage to the plastic, only when it is alone as a concentrate.
Finally, feel free to keep other color chemicals the same way, such as C-41 Flexicolor. There, I believe that the 'A' component does NOT have to be protected from oxygen and, happily, is NOT corrosive towards the PET plastic. I keep the C41 'A' in its original container, not airtight.
The 'B' and 'C' components of the Flexicolor C-41 process, however, must be protected, either in PET plastic or glass filled to the rim, as above for the RA4 chemicals. Again, even if mixed (or diluted) the C41 developer can be kept indefinitely in PET plastic filled to the very rim. - David Lyga
Last edited by David Lyga; 05-09-2012 at 08:47 AM. Click to view previous post history.