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

[Ulophot]

I have recently been running some tests in which I develop a single sheet of film at a time in my SP-445. I generally use D-23 1:1, which, conveniently enough, has a stated capacity of 4 sheets per 16 oz of D-23 1:1 (though it's not exhausted by then; some use it significantly more). As inexpensive as D-23 is, I would still prefer to use those 16 oz. more than once in such tests, if I'm doing them in one session.

The question, therefore, is, by what percentage do I increase the time for the second and third runs? (I don't mind mixing fresh for the fourth.) I used to reuse Microphen (a much more energetic developer, and I was using it stock-strength) for 9-10 rolls, increasing development 10% per roll developed, but that's my only experience with developer reuse.

[xkaes]

I'm not familiar with the SP-445, and it's been a while since I used D-23, but if you are mixing D-23 yourself, it's as close to free as you can get. Since I only use about two ounces of developer per 4x5" surface, I always use fresh stuff -- just to avoid any testing and calculations regarding re-use of chemicals. It's the same with stop and fixer.

But I do always run some basic density tests -- ONCE -- to determine the best time/temperature/dilution for my needs. After that, I don't need to change anything.

[Michael R]

Time compensation for unreplenished re-use depends on the developer and on variables including solution volume, and this assumes stock solution strength (such as your Microphen example). From a capacity perspective, D-23 should be similar to Ilford Perceptol, so I would suggest using Perceptol instructions and extrapolating. However generally you won’t find any directions from manufacturers for re-use of diluted developers as they are virtually always intended for one-shot use. This doesn’t mean you can’t try re-using D-23 1+1. What a mean to say is that you’ll have to figure out time compensation etc. empirically with your own testing. Any information out there on this will be anecdotal at best.

[paulbarden]

D-23 diluted 1:1 shouldn't be reused, period. If you want to use D-23 stock solution, then follow Michael's recommendation.

[Jim Noel]

D-23 is too cheap to use multiple times on expensive film. I can mix many gallons for the cost of one sheet of 5x7 film.

[Wheathins]

I have recently been running some tests in which I develop a single sheet of film at a time in my SP-445. I generally use D-23 1:1, which, conveniently enough, has a stated capacity of 4 sheets per 16 oz of D-23 1:1 (though it's not exhausted by then; some use it significantly more). As inexpensive as D-23 is, I would still prefer to use those 16 oz. more than once in such tests, if I'm doing them in one session.

The question, therefore, is, by what percentage do I increase the time for the second and third runs? (I don't mind mixing fresh for the fourth.) I used to reuse Microphen (a much more energetic developer, and I was using it stock-strength) for 9-10 rolls, increasing development 10% per roll developed, but that's my only experience with developer reuse.If d23 is similar to perceptol, ilford doesn't recommend reuse of any kind for diluted applications. When I use perceptol I use the most dilute combo and use one shot.

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[Tin Can]

Listen to Jim


D-23 is too cheap to use multiple times on expensive film. I can mix many gallons for the cost of one sheet of 5x7 film.

[Ulophot]

Soooo, calling me a cheapskate, eh? Okay, okay, fair enough. Down the drain it goes.

[Bill Burk]

If you have a sensitometer and densitometer, you can figure it out. Practically everyone has said it's not worth it and I agree.

But I have done a similar test and know how to do what you are trying to figure out.

Here are the steps: Include a sensitometric strip in each run of your processing. Read the results and graph them and determine the contrast from each test. Compare the results with a time/contrast graph (that you created by normally processing tests for several different development times).

I once performed the tests with D-76 1:1 re-used 3 times but developed for the same time.

My personal answer to the question "What happens if I re-use D-76 1:1 past capacity' but keep the times the same?": I lose 'thirty percent' contrast with each run.

[Bill Burk]

Soooo, calling me a cheapskate, eh? Okay, okay, fair enough. Down the drain it goes.

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...

[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?