The reality is Kodak, Ilford, Fuji etc all recommend using Stop bath OR a Water rinse when processing films. So who is out of touch ?
Not Dennis.
Ian
Yep. Which is why I'm with you. The water stop guys are so out of touch.
Out of touch with reality.? Only used water stop for the last 5 yrs with no problems but the water here is very soft so that maybe a problem to some and water the same temp as developer rinse 2x.
I am sort of wondering what was going through the guy's mind who first decided to ignore the instructions and just use a water rinse. Was he out of stop bath or just a contrarian? Was he trying to save a nickle or was he curious about what would happen? What else did he do? Did he decide not to change the oil or top off the anitifreeze in his car? Did his wife leave out the sugar in the cookie recipe?
The reality is Kodak, Ilford, Fuji etc all recommend using Stop bath OR a Water rinse when processing films. So who is out of touch ?
Not Dennis.
Ian
Ron Mowrey was a co-developer of TF-5 fixer. He commented many times about the compatibility of the TF fixers with stop bath. For example, a couple of posts here: https://www.photrio.com/forum/threads/alkaline-vs-acid-fixers.3850/page-2#post-49911
I am restricting my comments below to film processing, not print processing.
Let's think about it this way. What are the possible reasons for using an acid stop bath rather than a water "stop bath"? The way I see it, in the grand scheme of things there are two possible reasons.
1. Using an acid stop bath somehow yields better photos than using a water stop bath because an acid stop bath somehow produces produces superior negatives than those produced using a water stop bath.
2. Using a water stop bath results in faster degradation of the fixer than using an acid stop bath, by which I mean a measurable difference that also makes a practical difference. (For example, a 2% difference in fixer lifetime might be measurable, but is it different enough that anyone would care?)
This discussion is filled with endless speculation about these two points, with various people arguing pro or con, but what is conspicuously missing in the discussion is experimental evidence that supports the speculative arguments being made here.
So here is the challenge: Show us the evidence!
One subtle qualification to the challenge: It needs to be recognized that develop time might need to be (very) slightly adjusted to account for the fact that a water stop bath is slower acting than an acid stop bath. How much adjustment? I don't know, but as a wild guess I would think that shortening the development time by 15 seconds when switching to a water stop bath would probably be more than enough to compensate for this effect.
I am sort of wondering what was going through the guy's mind who first decided to ignore the instructions and just use a water rinse. Was he out of stop bath or just a contrarian? Was he trying to save a nickel or was he curious about what would happen? What else did he do? Did he decide not to change the oil or top off the anitifreeze in his car? Did his wife leave out the sugar in the cookie recipe?
More likely the use of a water stop bath preceding the use of an acid stop bath.
There was photography before Kodak, Ansco, and many others...
The reality is Kodak, Ilford, Fuji etc all recommend using Stop bath OR a Water rinse when processing films. So who is out of touch ?
Not Dennis.
Ian
I said I use water stop bath so what part of that didn't you understand?
A water stop is of course also a type of stop bath. It is just we usually refer to the special purpose chemicals like Ilfostop or Kodak Indicator Stop Bath colloquially as "Stop Bath", so the discussion here is about water stop bath vs. the other types of Stop Bath.
And my link to the Ron Mowrey posts was in response to those who say that TF-4 et al should not be used with (acidic) Stop Bath - he indicated that TF-4 et al is compatible with acidic Stop Baths - you can use those Stop Baths with them.
Even the Formulary material is inconsistent - in one part saying that acidic stop baths are not necessary, in others saying not to use acidic stop baths with TF-4 for prints.
A properly instigated, running water water stop is quite effective. If that is the workflow you prefer, go right ahead. Other implementations of a water stop are problematic.
If as you posted using water is so effective, why was so much money used in research and development for stop bath, as though there is no purpose for stop bath. There is a logical disjunction.
Because running water is way less efficient and effective for high volume commercial processing - the sort of environment that a lot of photo chemicals are optimized for.
But that does not stop the film development nearly as quickly as stop bath. Why would Kodak, Ansco and many others spend large amounts of money of R&D research for stop bath. Are you saying that they were addlepated?
You might not realize that when Kodak came up with the current color processes, C-41 for color neg film, and RA-4 for color paper, THEY DID NOT USE A STOP BATH. Probably more film and paper has been processed this way, including Fuji/Konica, etc., versions, than anything else in history (although I'm guessing on this). Anyone following the official process DOES NOT USE A STOP BATH.
I'm from an outfit where I spent years being personally responsible, as QC manager, to oversee the "process control," as well as the chemical analysis and final screening of all chemical mixes before use. In our main processing lab we ran several miles per day of C-41 film as well as a vastly larger amount of RA-4 color paper. My department also oversaw similar in several satellite labs, although they did not generally regenerate their chems. So I'm not just guessing at these things.
Having said this I should point out that these processes DO follow the developer with a lower pH bath that DOES halt the development fairly quickly. In the case of C-41 film this is a bleach; the first versions ran at pH ~6.5, as I recall. In the case of RA-4 paper this is generally a bleach-fix, aka blix, which combines a bleach and fixer together. The earliest version ran at pH running about 7.0, as I recall (depending on tank configuration - a single process tank ran a bit lower).
I should also point out a difference between commercial processing machines and small scale/amateur processing. The commercial machines generally use some form of squeegee between tanks, such that excess developer is stripped off the surface of the film before film enters the following solution. Then that following solution generally is mechanically circulated. Consequently there is little problem with "streaking" on the film.
In small scale processing, such as hand tanks, there's no clear way to quickly flush the developer off the film, so streaking could be a big problem. So it might be necessary to add a stop bath to the hand process.
Fwiw I'm specifically avoiding the topic of b&w films.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?