Stop Bath.. How important?

The films you cite are hardened, but probably do not use the more modern technology available to the major manufacturers.

If they were unhardened, they would be unsalable and unusable in today's market. You would be surprised at how soft unhardened gelatin is, and how easy it frills or reticulates.

PE

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Originally Posted by Photo Engineer

In the early days of photography, emulsions were unhardened or poorly hardened. This led to the formation of bubbles by reaction of carbonate from developer carryover to the acid in the stop bath or acid fixer. The reaction with an acid fixer can take place even with a short rinse of water.

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I have used acid stops for film and paper for over 30 years with absolutely no problem, but have had problems of one sort or another with using a water rinse after development.

I will continue to use an acid stop.

PE

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Thank you for that information! I've been educated. A prior poster described the proper way to fill a development tank (developer just above the level of the reels or single filled reel in a multi reel tank). I had no idea. I had been under the impression that the more developer you pour into the can, the better.

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Originally Posted by SchwinnParamount

Thank you for that information! I've been educated. A prior poster described the proper way to fill a development tank (developer just above the level of the reels or single filled reel in a multi reel tank). I had no idea. I had been under the impression that the more developer you pour into the can, the better.

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So what exactly would the results look like if you used too much solution in the tank? I, too thought more was better. I know sometimes not enough leaves for uneveness and you can see a stripe along the edge from not receiving enough developer. I also read somewhere in Adams 'the negative' about letting the film 'sit' in the water and not agitating it, but that was with Two Bath Developing. Is that the same or different?

Thank you.....

-Dorothy

"Too much developer" is when it doesn't "glug" when inverted. That means the agitation is less efficient. You get uneven and/or weak development.

Adams' water bath treatment is something completely different.

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Originally Posted by SchwinnParamount

I had been under the impression that the more developer you pour into the can, the better.

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If you completely fill the tank with developer then it is nearly impossible to obtain any agitation. Proper agitation depends on having some space for the developer to move about.

Developers like DS-12 which contain only a very small amount of carbonate are unlikely to cause pinholes. In order for bubbles to form the local area in the emulsion must be saturated with carbon dioxide.

Water and stop can work equally well although the acid can stop the development immediately. There is a grain penalty for either. I recommend you skip it altogether and go straight into the fix.

Ronald. Why is there a grain penalty for using water or stop? How noticeable is it? I don't think I had seen this as a reason for not using water or stop bath before?

Anyone else have any comments or experience of this negative aspect of water or stop?

Thanks

pentaxuser

I am going to be a devil's advocate here. If a filled tank is used with the reels on a lifting rod and the agitation being used is to simply lift the reel(s) and allow gravity to cause the reels to sink, other than some spilled developer I see no problem with this procedure..particularly an agitation problem.

I would believe it possible that some "staining" might take place..depending upon what someone means by staining..if the fixer is over-used.

I believe it damned near likely that using a stopbath could enhance the fixer's life...if the fixer is sodiun thiosulfate based and the stopbath is but a weak concentration of of apple acid.

I believe it is possible to create additional edge density, such as what was described, thru an ill chosen agitation technique when using roll film, particularly perforated roll film...this is not meant as saying that it happened in the case being discussed.

I've used a water stop for several years now (for films) and not noticed any problems of the sort mentioned above. But you should always use at least 3 changes of water and agitate continuously.

I have not used an acid stop bath in at least 25 years and have never experienced the problem you describe. However, I do know one of the causes of this problem.

If you put the reels in PHoto FLo youwill get the increased density along the edge because Photo FLo acts as a catalyst to the developer.
In order to remove traces of Photo Flo from the reels it is necessaryto scrub them in hot water with a toothbrush.

There has been two assertions now that I'd like to know chemical explanation for, from those that know of these things, including of course Jim.

1. Water or stop bath(presumably acid) gives a grain penalty
2.Photoflo acts as a catalyst for developer.

In the case of the second assertion I take it that this applies if photo-flo is allowed to dry on the reel or is there still a danger if the reel is simply rinsed under a tap but not scrubbed with a toothbrush under hot water? Is it the case that photo-flo, diluted considerably as it is, still cannot be washed of simply by a quick rinse under a tap?

I have to admit that I usually use a toothbrush but only because I want to be sure of eliminating one of the suggested causes of film sticking when loading onto a reel. Now there may be a second reason as stated by Jim Noel

However I do wonder if I am being over cautious and have toyed with the idea of simply rinsing the reel. It's so easy to get caught up in taking the "just in case" route and adding to the process unnecessarily.

On the other hand should there be a basis for both assertions then clearly there are grounds for taking both actions.

pentaxuser