David Lyga
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Hamlet did not have film to develop, but we do. (Besides he was a Prince, busy contemplating a revenge, of sorts.)
Every once in a while the question comes up as to whether a post-development water bath is sufficient to stop development. Many (including me) have feared that a bit of development would continue in a neutral water bath, unlike in the normal acid stop bath. However, lowering pH does not necessarily remove developer, it just makes it more acidic. In color work, actually removing the developer is necessary, as bleach and developer do not mix well. But this thread is primarily about B&W, thus my testing is along only those lines.
I have performed a test, several times just to be certain, that I hope to be definitive for both film and paper. My choice of film is Kodak ImageLink microfilm. I chose this film because even a slight increase in development time causes density to accumulate faster than with other films. I wanted irrefutable, air-tight data.
For the film test, I gave adequate exposure, then developed for slightly less than required for normal tonal rendition. That way, there was plenty of room for more density to form if there was developer present for that density to accrue. After three minutes of development I immediately cut the frame in two and plunged one half into stop bath. The other half I simply placed into clean water and let stay for three full minutes, undisturbed. During that three minute interval I fixed the first half. Then, after the three minutes were up, I placed the second half into stop bath and then fixed normally, all in complete darkness.
I washed the two halves and dried them. Then I compared. There was absolutely no difference in density.
For paper, I did this: I cut off a small rectangular piece of paper and fully exposed it to room light. Then, in darkness, I developed it for about half a minute, enough to cause only medium density to form. Again, still in darkness, I cut the rectangle in half and plunged the first half into stop, then fix. The second half I placed into clean water and let it sit, undisturbed for three minutes, then stopped and fixed. After washing and drying, I compared. Again, there was absolutely no increase in density with the water bath treatment.
In the pictures, WB shows which half got the water bath after development.
No increase in development happened once that film or paper hit the water. Not giving either agitation readily allowed any residual developer to act. The film and paper might have sill felt slippery because of the still high pH, but the developer was effectively neutralized once either hit that water. To me, at least, this definitively proves that development continuance is not a justifiable worry with the omission of the stop bath.
However, where problems can manifest are when the same water bath is used in, say, printing, and that water bath accumulates quite a bit of developer. It might, then, become a dilute developer in its own right. (I am not setting working standards here, merely being theoretical with my test.)
There is also a question that I have which seems to fit well at this point: Why does the pH in the whole process have to ever be lower than seven? Can alkaline fixers (see here):
http://www.monochromephotography.com/section233148_83765.html
work just as well, even BETTER (see the advantages listed in that link), given the data in the enclosed link? Why does there have to be ANY acid at all? Comments? - David Lyga
Every once in a while the question comes up as to whether a post-development water bath is sufficient to stop development. Many (including me) have feared that a bit of development would continue in a neutral water bath, unlike in the normal acid stop bath. However, lowering pH does not necessarily remove developer, it just makes it more acidic. In color work, actually removing the developer is necessary, as bleach and developer do not mix well. But this thread is primarily about B&W, thus my testing is along only those lines.
I have performed a test, several times just to be certain, that I hope to be definitive for both film and paper. My choice of film is Kodak ImageLink microfilm. I chose this film because even a slight increase in development time causes density to accumulate faster than with other films. I wanted irrefutable, air-tight data.
For the film test, I gave adequate exposure, then developed for slightly less than required for normal tonal rendition. That way, there was plenty of room for more density to form if there was developer present for that density to accrue. After three minutes of development I immediately cut the frame in two and plunged one half into stop bath. The other half I simply placed into clean water and let stay for three full minutes, undisturbed. During that three minute interval I fixed the first half. Then, after the three minutes were up, I placed the second half into stop bath and then fixed normally, all in complete darkness.
I washed the two halves and dried them. Then I compared. There was absolutely no difference in density.
For paper, I did this: I cut off a small rectangular piece of paper and fully exposed it to room light. Then, in darkness, I developed it for about half a minute, enough to cause only medium density to form. Again, still in darkness, I cut the rectangle in half and plunged the first half into stop, then fix. The second half I placed into clean water and let it sit, undisturbed for three minutes, then stopped and fixed. After washing and drying, I compared. Again, there was absolutely no increase in density with the water bath treatment.
In the pictures, WB shows which half got the water bath after development.
No increase in development happened once that film or paper hit the water. Not giving either agitation readily allowed any residual developer to act. The film and paper might have sill felt slippery because of the still high pH, but the developer was effectively neutralized once either hit that water. To me, at least, this definitively proves that development continuance is not a justifiable worry with the omission of the stop bath.
However, where problems can manifest are when the same water bath is used in, say, printing, and that water bath accumulates quite a bit of developer. It might, then, become a dilute developer in its own right. (I am not setting working standards here, merely being theoretical with my test.)
There is also a question that I have which seems to fit well at this point: Why does the pH in the whole process have to ever be lower than seven? Can alkaline fixers (see here):
http://www.monochromephotography.com/section233148_83765.html
work just as well, even BETTER (see the advantages listed in that link), given the data in the enclosed link? Why does there have to be ANY acid at all? Comments? - David Lyga
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