Question for chemistry--especially D-23--experts

[LabRat]

Any used developer will exhibit changes upon re-use (more & less)... Even if density is acceptable, the "look" of the image can change... Using months old used solutions means storage issues come into play also... And sludge/dust/debris can be carried over to new runs without filtering... Old film solutions seem questionable for the next run of important film after splashing around months ago...

Using stock solutions (carefully stored) and mixing working one-shot dilution minimizes some variables, using fresh every time (expensive) helps, or like me, mixing from scratch insures fresh, consistent every time...

Developer is NOT like fine wine... Does not get better with age...

Steve K

[xkaes]

One day you will be facing a deadline (like a friend's birthday and you want to give them a portrait), on your last batch of chemicals, and all the camera stores are closed...

Just one more reason I mix my own. They are always available, always fresh, and per sheet, basically free.

[j.e.simmons]

There’s a thread on photrio about using D23 1:10 with .5g sodium hydroxide per liter of working strength added.

[mdarnton]

I use D23 1:7 for xray film. That would solve your problem but I haven't tried it that dilute with regular film. When it quits it doesn't slow down it stops dead, so you need to stay safely clear of that.

For that use it lasts a couple of weeks in the tank, so you can save it. Always test before you believe what anyone says, including me.

[Doremus Scudder]

Philip,

How often do you do tests with just one sheet? If only occasionally, then I'd think the waste was worth it for the accuracy of the test. Alternately, maybe you can structure your tests so that you have a complete number of sheets to develop at once (that would also duplicate more closely the usual fluid dynamics in the tank than developing just one sheet at a time).

Testing to find the percentage difference for subsequent sheets is bound to use up time, film and chemicals, and likely not worth the effort. Guesses are approximate (e.g., just adding 10% to the last development time for each subsequent sheet). How precisely do you need to measure whatever it is you are testing?

Best,

Doremus

[Ulophot]

Doremus, not that often. I find myself doing more testing in part because I can't make the photographs I want (portraits) for now. So, i push the proverbial envelope a little more in this or that direction to see what result I get. I'm using an SP-445, which needs 16 ounces. For instance, I was recently testing extended development times with HP5 at 400; my starting point is 200, but these were very-low-range, interior self-portraits in relatively dim light (5-6 sec @ f/11). Very useful exercise, but one sheet at a time.

It's not the expense so much as knowing that the developer is not getting used up tank after tank. Paper is far more expensive, of course, and, even as frugal as I am obliged to be, I keep in mind Walter Rosenblum's advice to "print as if someone else were paying for the paper." You have to push to learn.

[Jim Noel]

There’s a thread on photrio about using D23 1:10 with .5g sodium hydroxide per liter of working strength added.

This is no longer D-23!!

[Drew Wiley]

I suspect more than just contrast would be affected through re-use, but also some change in grain clumping structure and edge effect. Reminds me of re-heating the previous day's coffee in a microwave. Just ain't quite the same. I haven't personally used D23 for a long time; but yeah ... it's so darn cheap to mix up fresh, why gamble?