Print developer working solution lifetime

I use D-72 1:2 solution to develop my fiber prints. How long can I keep reusing the working solution?
I see an image emerge after about 15 seconds. Should I be monitoring if this time changes and then replace the working solution completely?

*D-72 is sold pre-packed here in Japan. It has A and B pouches and mixes easier than Dektol. It also comes in 1L packages and is much cheaper.

I do 12 prints in a tray then dump..but that's me

Dektol is Kodak's pre-packaged D72 and an MQ developer, tray life is shorter than an equivalent PQ developer, probably 2-3 hours but a lot depends on the volume of developer and the number f prints. You will notice it slowing down as it exhausts or oxidises.

Ian

Kodak’s data sheet suggests one day or 32 8x10 prints per liter.

http://imaging.kodakalaris.com/sites/prod/files/files/product-categories/e103cp.pdf

ericdan said:

I use D-72 1:2 solution to develop my fiber prints. How long can I keep reusing the working solution?
I see an image emerge after about 15 seconds. Should I be monitoring if this time changes and then replace the working solution completely?

*D-72 is sold pre-packed here in Japan. It has A and B pouches and mixes easier than Dektol. It also comes in 1L packages and is much cheaper.

Click to expand...

You can always use it until you notice that the blacks are getting weak. Then, it's time for a new working solution; develop for a fixed standard time to keep things consistent. my time is three minutes at 20C.

I use a home brew version of Dektol/D-72 at full concentration, and this soup lasts for many months, depending on use, of course. Typical indicators of when the soup gets weak are:

1. strange swirly patterns in areas which should be uniform
2. weak blacks
3. slow action, prints take much longer than they should

If you use a more concentrated developer, it requires more Carbon Dioxide to effectively lower it pH, more Oxygen to use up its Sulfite and whatever dev agents it uses, yet solubility for gases goes way down with concentration. As a result you get a developer with substantially better shelf life.

RalphLambrecht said:

You can always use it until you notice that the blacks are getting weak. Then, it's time for a new working solution; develop for a fixed standard time to keep things consistent. my time is three minutes at 20C.

Click to expand...

Is this at 1:2 ?

ericdan said:

Is this at 1:2 ?

Click to expand...

Yes, it is!