a few questions

So I've been looking for an answer to this for a while but is there a way to test part used working strength chemicals for paper/film (I use a universal dev and fix)
Also when washing a print in a running water tray will a slow flow be ok or doses it near to flow relatively fast? I use RC paper 12x16

You're the Guru tell us

In 50+ years I've never needed to test a developer, you can use a 35mm film leader to test fixer.

RC prints need very little washing so slow is OK don't waste water . . . . .

Ian

There are several indicators which tell you that paper developer is about to keel over:

1. development gets slower and slower
2. supposedly deep blacks aren't as black any more
3. some exhausted/oxidized developers tend to create swirly patterns in supposedly homogeneous areas

If either of these happen, throw out the print, replace the paper developer and redo the print. You are not going to start with 40x50cm paper, but rather small test strips to dial down exposure, so no harm done.

With film developers I would be a lot more cautious, since a reshoot typically means a lot more extra-hassle than a reprint. Even if a test strip turns black in room light, there is no guarantee that the film developer has not changed such that it creates lower contrast, lower film speed, higher fog, or some nasty combination thereof. If you are not confident, that your batch of film developer works as expected (e.g. by following the instructions to the letter), do yourself a favor and use fresh stock.

Some developers don't keep well once mixed to working strength due to exposure to air and to combination with water. Check the instructions from the developer maker for guidance on keeping properties.

My policy is to follow the guidance, I feel that the effort that goes into making an image in the camera should not be exposed to the risk of poor results through keeping chemicals too long, chemicals are replaceable, camera images are unique.

Rudeofus said:

With film developers I would be a lot more cautious, since a reshoot typically means a lot more extra-hassle than a reprint. Even if a test strip turns black in room light, there is no guarantee that the film developer has not changed such that it creates lower contrast, lower film speed, higher fog, or some nasty combination thereof.

Click to expand...

If there isn't any reliable test then are we governed solely by manufacturer's storage times?

pentaxuser

As others have said, there are tests for fixer. As to speed of wash water, Kodak recommends a flow rate equivalent to 12 complete changes of water per hour, or one complete change every five minutes, that's slow.

To the OP (the guru):
Welcome to Photrio!
There are some tests. But for printing chemicals, it probably makes more sense to use your chemicals once or maybe a few times in a short period, and then discard them.
Unless you are using chemicals that are designed for multiple re-use, over an extended period of time. The chemicals that have that feature tend to advertise that in the materials supplied by the manufacturer (Liquidol comes to mind).
One small request: when you choose a thread title, it really helps to make it a bit more specific!
Something like: "Is there a way to test part used working strength chemicals for paper/film?"

pentaxuser said:

If there isn't any reliable test then are we governed solely by manufacturer's storage times?

Click to expand...

There are very simple tests for checking whether a fluid in the widest sense reduces silver halide to silver, i.e. develops/blackens test clips in room light. But a decent developer is not just a fluid which reduces exposed silver halide, that not what you pay money for

You pay money to get predictable contrast across the range of exposures, full film sensitivity, low granularity and decent sharpness, ideally all at the same time, or a carefully chosen balance thereof. You can test this with carefully exposed test strips, densitometric and MTF analysis and interpretation of results, and you still won't be sure whether the soup, which just performed so well, will do this again with the next roll you process - the actual roll you want to develop. It's a bit like checking whether a match works. Heisenberg's principle of uncertainty says "hello!".

Or, and that's the path most people chose: you trust manufacturers with their vast knowledge&experience, that their developer solution prepared and used according to their instructions will work reliably. This will allow some perfectly good developer to go to waste prematurely, but think of it: even oh-no-so-expensive DD-X is profoundly cheaper than any fresh roll of film you'll ever process with it. And even the most expensive roll of film should be cheaper than the effort and diligence and preparation and effort you made when you exposed it.

pentaxuser said:

If there isn't any reliable test then are we governed solely by manufacturer's storage times?

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No. There actually are extremely reliable tests. Chief among these are the actual processing of a test film which is representative of one's production film. Other possible tests, which are mostly beyond the realm of the hobbyist, might include various chemical analysis, intended to see how "used up" the developer is.

The bottom line of what someone should do ultimately depends on the "value" of one's film vs the "cost" of doing "tests." For example, if you have photos of immense value, perhaps to settle a life or death court case, or to prove the existence of aliens from outer space, would you just develop with the regular bottle sitting on your shelf? I don't know for sure how far I'd go, but at an absolute minimum I'd test process something else immediately prior.

Rudeofus said:

You can test this with carefully exposed test strips, densitometric and MTF analysis and interpretation of results, and you still won't be sure whether the soup, which just performed so well, will do this again with the next roll you process - the actual roll you want to develop.

Click to expand...

Well sure, I agree that you won't be ABSOLUTELY certain, but... provided that one is following good practice and guarding against foreseeable accidents, then the statistical likelihood is extremely high that the test roll is a good predictor of the following roll.

From personal experience - I spent a number of years overseeing the "process control" in a very large processing lab; running thousands of gallons of replenishers every day - I don't recall EVER seeing a developer change happen as quickly as "the next roll." For a little perspective on what we looked at, we ran somewhere around 50 control strips every day in our main lab (multiple processing machines); one of my techs spent nearly half their workday dealing with this sort of thing.

I made reference to "good practice," which covers a lot of things. This would include such things as using an "adequate" amount of solution for the quantity of film, keeping minimal aeration in the developer, relative to the amounts of development, and that sort of thing. In general, following the recommendations of a reputable manufacturer would be good practice.

Not really an answer to the question, but my solution is to use developers and chemicals for film and papers on a one shot basis because my darkroom work is scheduled irregularly. Except for fixer and bleach for reversal processing I don’t reuse chemicals.

It sounds as if you are saying, Mr Bill, that the tests that there are, may be beyond the equipment or expertise of the average darkroom enthusiast so to be on the safe side use the manufacturers storage times as Rudeofus has suggested. I am sure this is the 100% way of ensuring quality. By definition this has to be the 100% sure way.

However, for what it is worth to the OP, my experience with Xtol and using the "black leader test" appears to have resulted in success with Xtol that I had stored way beyond Kodak's suggested storage time. Would the films from the older Xtol have produced the right "readings" when subject to the kind of tests that a proper "Process Control " regime involved, I cannot say. All I can say is that the negatives looked the same as earlier processed negatives and so did the prints.

For the OP's info my black leader test consists of processing the leader in the same dilution of Xtol as will be used for the actual film and for the same time and at the same temperature, then a quick fix and dry and holding the "black" leader up to a clear incandescent 100W light bulb and checking if the tungsten filament has about the same brightness as in previous tests.

The first time the leader went less black, it was a noticeable difference and the Xtol was then dumped. Interestingly I kept a little of the exhausted Xtol and checked it against fresh Xtol. The exhausted stuff had by itself looked pretty clear but against the fresh stuff was very slightly pale straw coloured.

pentaxuser

pentaxuser said:

It sounds as if you are saying, Mr Bill, that the tests that there are, may be beyond the equipment or expertise of the average darkroom enthusiast so to be on the safe side use the manufacturers storage times as Rudeofus has suggested. I am sure this is the 100% way of ensuring quality. By definition this has to be the 100% sure way.

Click to expand...

Hi, well I guess I didn't straight out say it, but the average home enthusiast COULD just process a short strip of their own film, then compare it, perhaps on a lightbox, to an "ideal" processed neg, ideal being when the developer was new. So this would be probably the best test without special equipment, imo. But I dunno if it's worth the trouble for most people, including me. For non-critical stuff that I could reshoot, if necessary, I'd mostly just go by manufacturer recs.

Regarding the manufacturer's storage times, etc., I think it somewhat "depends" ... I've only ever been familiar (somewhat) with municipal water in the US and one area in Canada, but I know there are at least some significant variations. So there are likely some water supplies where the published recs don't hold up, but I'm just guessing. (We had another division with something like 600 minilabs, but each location was prescreened, including looking at the available water, prior to putting a lab there, so we never worked with really bad water.)

I will say that I'd trust Kodak's published (for the general public) recs as much as anyone's; in my experience they tend to be pretty conservative (towards protecting the user). But I'm not sure I'd trust Xtol in flaky water, without a personal verification that it seems to hold up ok for whatever the spec storage life. I don't know enough about Xtol to really have a legitimate opinion, but there has been enough internet talk to worry me a little. (My local water is pretty decent for photo work, so I won't personally run into that issues.)

One comment on the black leader test; my only concern is in the possibility of a chemical "fogging" situation, which again, I don't know if this is a possibility with Xtol. To explain what I mean, look at the color developers. If you contaminate them with bleach, you can get a really strong chemical fog on your film. I don't think you'd see this on a black leader test, which might lead you to think the developer is ok when it is not. Again, I dunno if this is a possibility with Xtol, but in either case.the test of processing a "normal" test neg would still be a reliable test. Just my two cents.

Thanks Mr Bill. Both the guru and I are located in the U.K. where nearly everyone's water is out of a tap from one of several, highly regulated water companies. Based on recent tests which each water company is required to carry out and put into the public domain. I know I live on one of the hardest water areas in the U.K..It's the kind of water that forms limescale on taps and inside kettles but I have never experienced water issues when processing film. I don't know where guru lives in the U.K. but there's a fair chance that his water might be better.

Yours and Rudeofus' posts made me think about the whole matter of "leader testing some more. I have noted your fogging example but do not know either whether this applies to B&W film processing.

Can either of you in as simple layman terms as possible commensurate with covering the "Whys", say what it is about the "black leader " test that could be unreliable in terms of the developer's qualities. I had assumed that if the developer was good enough to turn the equivalent of the highlighted part of the film black then it would have the correct proportional effect on the rest of the film?

Thanks

pentaxuser

I always use fresh chemicals when processing film and printing, so no need for testing.

pentaxuser said:

Can either of you in as simple layman terms as possible commensurate with covering the "Whys", say what it is about the "black leader " test that could be unreliable in terms of the developer's qualities. I had assumed that if the developer was good enough to turn the equivalent of the highlighted part of the film black then it would have the correct proportional effect on the rest of the film?

Click to expand...

Not all developers lose activity right away as they oxidize. I remember mixing a variant of MCM-100 with CD-4 a while back, and after a few weeks of storage its pH actually went up! A clip test in room light would have shown this old batch in perfect order, when a roll of correctly exposed film would have shown severe fogging. Another example is slow but steady degradation of activity: E6 FD loses activity slowly, and while test clips in room light will report everything as ok, the actual slides will turn out way dark. Xtol is one of the very few examples of a developer, which holds activity steady for a while and then drops like a rock - this might be one example where a clip test is telling.

Conclusion: a clip test is better than nothing, but you should invest more diligence if the negs are important. Either gain experience with the developer you use, or follow the manufacturer's instructions to the letter.

pentaxuser said:

I have noted your fogging example but do not know either whether this applies to B&W film processing.

Click to expand...

I also do NOT know if this "fogging" example can apply to any B&W process, but I suspect not. (My expertise is mainly in the color negative/print processes.)

To be clear, I CAN NOT answer definitively if there are any possible problems with the black leader test in B&W processing.

Thanks for your further replies. If I may summarise what each of you(Mr Bill and Rudeofus) have said.
Mr Bill:The fogging example may not apply to B&W black leader tests
Rudeofus: Your examples of potential defects in the black leader test seem to be connected with colour film also

I think you are right about Xtol's sudden drop in strength but in my experience this showed up quite clearly on the black leader test. I use Xtol exclusively so cannot comment on the efficacy of the black leader test with other developers, nor can I state categorically that in those developers that deteriorate slowly it would always be possible to see by eye that the same incandescent tungsten wire in the same bulb has slightly brightened although the naked eye is pretty good at this kind of differentiation. However what I think is possible is to retain the black leader from fresh developer and compare with subsequent leaders in front of the same bulb. Certainly then, I'd be fairly confident of detecting even a small difference and this is in fact what I do and would recommend the OP to do .

The OP seemed to be concerned with tests for efficacy so may have doubts, as do I, that developers may be thrown out too soon. Thus the black leader test may be the kind of test that would be useful. Neither has he said if he is looking for a reliable test for colour developers, in which case the black leader test, being for B&W film, is not appropriate.

If you are still following this thread, guru, I think the black leader test is worthwhile and hope the responses to this thread has helped

pentaxuser