What formula are you using for Divided D-23?

[Michael R]

Considering the cost of Large Format film and other materials, the savings we obtain by reusing developer may be relatively modest.

If I were doing an important project I would want to be confident that my developer is always the same.

Agree completely. D-23 and two-solution variants thereof are pretty cheap, requiring nothing exotic. A goal with any process is consistency. In that context I would not recommend reusing D-23, on its own or in a two-solution process, unless it is properly replenished. Even so, replenishment of a metol-sulfite developer is still a compromise, and usually makes more sense in a high volume process (which is why D-23 was originally formulated as an alternative to D-76). For the most consistent performance, I would always suggest using it one shot even at full strength (as well as at 1+1, 1+3 etc. of course).

@gabriele: I will try to answer your questions later today.

[Tin Can]

Why is it that people insist on messing around with a tried and true, well proven developer rather than using it as intended? D-23 is not meant to be diluted. If not, there is essentially no limit to it's use if not contaminated. At the college we used it in N2 burst system with replenishment for a semester at a time. Probably around 4500-5000 sheets of 4x5 per semester. When it was changed, I brought it home to use for total development. I have never known it to go bad, or get weakunless contaminated.

Jim, that's great info. How large were the tanks? How many gallons?

[sanking]

Agree completely. D-23 and two-solution variants thereof are pretty cheap, requiring nothing exotic. A goal with any process is consistency. In that context I would not recommend reusing D-23, on its own or in a two-solution process, unless it is properly replenished. Even so, replenishment of a metol-sulfite developer is still a compromise, and usually makes more sense in a high volume process (which is why D-23 was originally formulated as an alternative to D-76). For the most consistent performance, I would always suggest using it one shot even at full strength (as well as at 1+1, 1+3 etc. of course).

@gabriele: I will try to answer your questions later today.

I agree with Michael (and Ken) in that for most consistent results one-shot at full strength is the best way to go. Reusing developers like D-23 is feasible, but requires a dedicated system (as Jim describes) or a good system of replenishment.

In the article I published in View Camera I used one-shot and discard solutions because it is the only way to I know to closely test with sensitometry. All re-use systems I have tried always wander a bit in terms of average gradient so not practical for exact testing, though may be OK in practical use. This comment applies not only to D-23, but to all developers.

Sandy

[steveo]

Thanks Sandy I see where you're coming from.

Whilst Metol is cheap, I agree its inexpensive, its not readily available in the UK (or the EU); Mine is still waiting in customs after 3 weeks minimising its use is less for the economy more for convenience of not having an enormous back log when HM Customs finally let it be delivered.