Why DIDN'T I use stop bath before?

[alan_gage]

Hi all,

 

I realize many of you already do this; but many don't as well.

 

I started developing my own film and prints a little over a year ago

and have really enjoyed it. The whole time I've been using a water

stop bath for my film and paper. It seemed nice to have one less

jug/tray and chemical to worry about. I'd read some people who

disagreed with using water stop; but most people got along just fine;

and so did I.

 

Then a couple weeks ago I started thinking about how it might actually

be easier NOT to use the water stop. When using a water stop bath with

film I'd fill the tank twice and agitate before fixing it. With paper

I had to transfer the paper to my washing bin for about 1/2 minute

before fixing. It seemed like it might be faster, more convenient, and

less wasteful of water to just use an acid stop bath.

 

So last weekend I went and bought myself some acid stop bath and

Ilford rapid fix (was using TF-4 which specifically says don't use any

acid stop with it) and mixed it up. I've used it for a couple print

sessions and a few rolls of film now and must say I'm real happy with

it this way. It's so much nicer to be able to go directly from the

developer-stop bath for about 10 seconds-and straight to the fixer;

particularly when developing prints. I don't know how I convinced

myself before that using a water stop bath was the "easy" way.

 

I thought perhaps the smell would bother me; but so far during my

roughly 3 hour print sessions I haven't thought the smell was

objectional enough to turn on the vent fan in my small basement

bathroom/darkroom.

 

You might want to give it a try.

 

Alan

[johnmarkpainter]

It all depends on whether you want to be in the TF-4 cult or not.

 

I use water Stop and TF-4 with Film and use Ilfostop and Heico Fixer with my Paper.

 

jmp

[rowland_mowrey]

I believe that you can use a stop bath with TF-4. You just need to make sure that you wash about 2x longer than they suggest, and also you will probably need to use 2 fix trays or replace your fixer just a little more often.

 

It is really no problem.

 

Ron Mowrey

[theumguy]

I know that i don't use the stop bath for my film, but i do for my prints always. I don't know what it is, i just find that for whatever reason, my prints need it, and my negatives just don't really turn out any different. just my two cents i guess.

[pics]

I just bought some TF-4 and had planned to continue using an acid stop. I know they say you dont have to but never realized it was not recommended. Is there harm to be done buy using an acid stop with this fixer?

[rowland_mowrey]

Daniel;

 

Read my post above.

 

Ron Mowrey

[continuity]

I don't use it for film anymore, but I definitely use stop for prints.

 

I believe the stop does more than stop the development with paper, it also neutralizes some of the other chemicals in the paper.

[dean_williams]

There's really no need to guess weather you should use stop bath with TF-4. Just read the bottle that the manufacturer ships it in. Says right on it in bold letters "Do Not use an acid stop".

[lowell_huff1]

To make your experience in the dark room less of a problem with objectionalbe odors, we make odorless stop and fixers. Water bath is not a stop bath. You must change the pH on the emulsion to stop development.

[silent1]

What I see as the main reason to avoid acid stop bath is soft emulsion. If you use Efke or J&C Pro 100 films, acid stop batch may cause (or accentuate) problems with the emulsion -- pinholes, or little bubbles that aren't quite pinholes. J&C swears up and down this is the primary cause of problems with the J&C 100 (and I want to like this film, at $1.39 per roll including a black film can that fits 120). So, I've started using a water stop.

 

You also shouldn't use acid stop (regardless of the fixer you use) if you use a developer with a strong carbonate alkali -- like Diafine. The carbonate can and will generate carbon dioxide gas on contact with acid, and that gas can cause problems even in emulsions that aren't normally significantly affected by acid stop baths.

 

If you never use soft emulsion film, and never use a carbonate alkali developer, then it's probably better to use stop bath than not; you'll get better consistency by stopping your development when you expect to instead of "somtime over the two minutes it takes to fill and agitate the tank twice".

[rowland_mowrey]

Dean;

 

The reason that the bottle of TF-4 says not to use stop bath with it is so that you get the maximum wash time reduction. TF-4 was designed to achieve this by being alkaline. If you use a stop with it, all you have to do is lengthen the wash time to compensate.

 

The other thing that you should do is use 2 trays of fix so that exhaustion does not become troublesome due to any pH drop in the fix caused by the stop bath.

 

Lowell;

 

A stop bath can be any pH. All it must do is stop development. If that were not so, then plain water would not be effective. I know of several neutral, near neutral and alkaline stop bath formulas.

 

Ron Mowrey

[pics]

Ron:

I read your post but I guess I was wondering what the Formulary puts in TF-4 that would make them say its not compatible with an acid stop. I won't use one now that I know but I was just curious thats all.

[pics]

I typed too slow. Thanks Ron.

[dean_williams]

Ron; In my normal developing practice, I always use a stop, and regular (rapid or powdered) fix. Mainly, I want the stop to preserve the life of the fixer, with the rapid development arrest being a bonus when using short dev times. When I do use TF-4 I use a water bath for just the reason you pointed out above. Acid stop will certainly shorten the life of TF-4.

[alan_gage]

"If you use Efke or J&C Pro 100 films, acid stop batch may cause (or accentuate) problems with the emulsion -- pinholes, or little bubbles that aren't quite pinholes. J&C swears up and down this is the primary cause of problems with the J&C 100 (and I want to like this film, at $1.39 per roll including a black film can that fits 120). You also shouldn't use acid stop (regardless of the fixer you use) if you use a developer with a strong carbonate alkali -- like Diafine. The carbonate can and will generate carbon dioxide gas on contact with acid, and that gas can cause problems even in emulsions that aren't normally significantly affected by acid stop baths."

 

I wasn't aware of the problem with J&C films and developers like Diafine. I do have some Diafine mixed up but don't use it very often. I was also thinking of trying some J&C film in the future.

 

I guess I'll make sure I keep some water on hand for those cases.

 

Thanks,

 

Alan

[bill_troop1]

My thanks to Ron for letting me know about this interesting thread. I did not realize that the instructions for TF-4 have a blanket advisory against using acid stop baths. I will have to look into that. There is a brief section in FDC on p. 106 which sets forth a useful technique for employing acid stop baths with alkaline fixers (or neutral fixers, or near-neutral fixers -- for example, slightly acid fixers where you do not want to raise the pH to neutral, as could happen if you used a typical acetic acid stop bath):

 

"It is possible to use acid stop baths with alkaline fixers when you need to stop development on the dot and in order to suppress edge effects--for instance in scientific photography and astronomy. Simply rinse the film in running water for 30 seconds _after_ the stop bath but before the fixer. This will keep acid from being carried over into the fixer. Alkaline stop baths are still experimental. See Appendix 1 for suggestions."

 

In other words, yes, you should not place an acid bearing material straight into TF-4 -- even though it is so well-buffered that pH would still probably not fall below neutral. Instead, you should wash briefly in water, after the stop bath and before the fixer. Under those circumstances, you will still be getting the rapid washing benefits of alkaline fixers. (Even so, you would need to add a _lot_ of acid to TF-4 before you reduced the pH to the point where rapid washing did not take place. TF-4 is very well-buffered--that is why there is a sediment in the stock solution.)

 

However, let's look at some other things.

 

1. The important point has been raised that using a stop bath saves on water. This is absolutely true. However, an all-acid washing sequence will _not_ save on water ultimately, because although water is saved at the _stop_ step, much more water is needed at the _washing_ step.

 

2. As Ron points out, the stopping of development has never required a pH change. (Lowell, since you aren't aware of this and yet do manufacture photo chemical products, let me tell you that there are suggestions for experimental alkaline and neutral stop baths in FDC. Why don't you have your company put some R&D into them? That would be a valuable service to photography.) Stop baths can be made at any pH. However, I doubt that any practical neutral or alkaline stop bath is as _rapid_ as the 10% buffered acetic acid/sodium acetate stop bath solution I recommend on p.104 of FDC. That's an expensive stop bath to use, compared to 2% acetic acid, but it works so much better, and avoids the possibility of pinholes and reticulation, that I can't understand why anybody who needs to use a stop bath wouldn't use it. However, of all the suggestions I have ever made, it seems to be one of the least popular.

 

3. Intuitively, it seems to me that if you are going to use a stop bath, it is much more elegant to use an acid fixer as well. However, you will still be using much more water because of the longer washing times you need, and that unnecessarily consumes both time and water, two resources, especially the former, we can never have enough of.

 

4. I realize I am flogging a dead horse, but let me reiterate my belief. If you are going to use a stop bath, there is no point in using one that doesn't stop development rapidly. 2% acetic acid does not stop development rapidly. 10% buffered acetic acid/sodium acetate does. The very elegant Kodak study which sets this forth is "Replenishment of the Film Stop Bath", PSA J., 17B: 13 (1951). That is one of many references I should have but did not include in FDC.

[peter_svensson]

I was having problems with stains on RC prints when going from Neutol WA developer to Agfa FX Universal fix. I tried acidifying my water stop, but that did nothing. What did work was extending the time in the bath to 30 secs and agitating a little bit to really get the developer out of the paper. Confirmed my belief that the acid is beside the point.

[rowland_mowrey]

Guys;

 

Bill Troop is 100% correct!

 

There are many ways to stop development before going into TF-4, and a stop bath is one possibility. What form it takes, and the process sequence depends on the product(s) involved and their physical properties.

 

Ron Mowrey

[johnmarkpainter]

Aha!

 

Now I know why I use water stop and TF-4 :) Knowledge is power.

 

P.S. I LOVE Edge effects.

 

jmp

[rowland_mowrey]

John;

 

Sometimes you can have too much of a good thing.

 

Sometimes there are side effects such as non-uniformity within one film frame or over several rolls of film.

 

The stop is there, and was introduced many years ago for good reason.

 

Ron Mowrey

[david j.lee]

i use water for film because stop bath does funny things to my negatves. i

always dump the fixer anyway. with paper i always use a stop bath.

[bill_troop1]

Ron has a bee in his bonnet about edge effects, and for good reason. His is the only prominent voice out there noting that you don't always want edge effects from your developer. I wish we had discussed this more in FDC, and had managed to produce illustrations showing the quite different edge effects that you will get, for example, if you shoot the same subject on 35mm film, and on 4x5 film, but develop in the same acutance-enhancing developer and by contrast the same non-acutance developer. Geoffrey Crawley has well-described the situation that occurs in a dilute developer: each frame becomes its own little developing lab. The corollary is that processing uniformity goes out the window, and processing uniformity is very important to Ron. Personally, I'm willing to take the risks. I don't, myself, mind, all that much, if a frame has bromide marks around the sprocket holes, or if there is halation, or other gross edge effects that you will tend to see using extreme acutance techniques such as stand or near-stand development. But the perspective of one who keeps conventional technical excellence uppermost in mind is always welcome. It really is a complex situation that deserves more discussion.

 

All of that said, I don't think that a water-rinse, in and of itself, is capable of _drastically_ altering the degree of edge effects in development. Yes, a water rinse will enhance edge effects - often for the good, and occasionally for the bad. But to get a _very_ high degree of edge effects, you must develop in a very dilute developer, and must agitate substantially less than normal. Conversely, to avoid edge effects, you must use a developer that will not exhaust much, and must agitate normally. In either case, the major effect you get - low acutance or high acutance - will be set by the way you developed, not by whether you used a true stop bath or water rinse.

 

In other words, if you have developed for low acutance, and use a water stop, you will gain slightly more acutance than if you used a stop bath. If you have developed for high acutance, you will only get slightly less of an acutance effect if you use a stop bath instead of a water rinse.

[rowland_mowrey]

I agree with Bill. I was just discussing this with him and he has made some good points.

 

I would like to point out that as a general rule, a 100 micron line, a 10 micron line, and a 1 micron line define average object line thickness for LF, MF and 35mm films. Therefore the optimum film and developer combination will give the same result with one scene in all 3 formats (4x5, 120, and 35mm) with the same contrast and sharpness from the relative formats at equivalent enlargements. Ideally, the only difference would be grain.

 

If you mess with edge effects too much, then your variation with films and between formats will cause swings in sharpness, edge effects and apparent contrast (image contrast is a function of the edge effects at your magnification).

 

Stop baths used with films tend to damp out or minimize this effect in B&W. In color, the use of DIR and DIAR couplers control this to a large extent as do interlayer and intralayer effects.

 

Ron Mowrey

[johnmarkpainter]

Very informative thread.

 

I have also been gravitating towards higher Dilutions and less Agitation over the last 6

months. I had no idea what the science was...just liked the look.

 

Mr Troop,

 

YES I have read your books :) I'm just not a chemist at heart. Thanks to all the scientists

here for letting me "copy off of your Final Exams" !

 

jmp