Good point, Matt.
Originally Posted by MattKing
I always expect people to avoid the endpoints when a range is given, but that's perhaps an invalid __assumption__.
“Wise men talk because they have something to say; fools, because they have to say something.” - Plato
I have been crunching the data and have recently come to the conclusion that you can lose 2/3 stop film speed by developing in open tray shuffling stacks of sheets.
Quality of the negatives is still sublime, but the speed is gone.
Any speculation as to why that might be, Bill? I haven't particularly noticed it, but I'm not measuring that carefully. I'd be hesitant to correlate speed to a particular development method in a blanket way. Factors (some of which overlap) could be, among others:
Originally Posted by Bill Burk
--More agitation with shuffle method causing higher contrast, shorter development time, not leaving enough time for shadows to develop.
--Developer choice and oxidation.
--Aerial fog from shuffling (could be related to developer choice as well).
--Fog from light leaks in the darkroom being a bigger factor with open trays than other methods.
One thing that I'm careful about is to time the shuffling speed so that I always cycle through the stack evenly, for instance, one cycle every 30 sec., whether it's 4, 6, or 8 sheets.
A few things made me think sheet stack shuffling is the culprit. I don't think sloshers are affected unless you stack within slosher compartments.
-Tank developing roll film gives me full speed.
-ASA specifications require a specific kind of agitation - and physically this seems at odds with that.
-When I developed two sheets emulsion to emulsion I had significant ghost effects.
I get no significant fog (0.05 at 16 minutes). Plenty of time for shadows to emerge, 13 minutes is my normal time. This remains fairly stable my agitation is by feel, about 5-10 seconds per sheet (I begin with faster agitation to ensure the sheets do not stick together). I use no presoak. I don't turn the film 90 degrees (though that is recommended by manufacturer).
I am open to suggestions of things to change.
For example Leigh suggested developing a single sheet.
Other things I might try:
Traditional film like Tri-X
Could be the choice of film--my own preference is for traditional grain films.
Ghost effects I've never noticed, but I always stack the film emulsion side up. I occasionally have to process one or two sheets, but I prefer to process more like 4-8, so that cold be another issue.
One thing I haven't done enough of is monobath processing in trays for single sheets. I suppose when I was first experimenting with monobath processing I tried storing the solution in a flat plastic container that I could process 4x5" in, but I gave this up when I learned that once you start using it, it's not worth using the next day. I've done it with tanks and hangers for 4x5" or 2x3", but since it's an inherently low-agitation method, it might work well with a single sheet in a tray, and that could be attractive for ULF. I still don't feel 100% confident, for instance, shuffling 7x17", just because I don't shoot enough of it. I wouldn't shuffle in a monobath, because the solution is strongly alkaline and softens the emulsion, and it's too prone to aerial fog effects and overagitation (which speeds up the fixing process more than the development process), but for single sheets it might be just the thing.
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I understand the preference for traditional grain, it's what I use for roll film, and a traditional grain roll film clued me in to this issue. But I seem to get full speed on TMAX 400 roll film - and the difference is small tank vs tray.
Originally Posted by David A. Goldfarb
The ghost effect came about from an error, I accidentally flipped one sheet over. But it illustrated that the two emulsions were competing for limited developer. X-ray film users may need to be alert for this. But it will not normally happen if you always develop emulsion up.
I'm pretty excited by this finding. I think there could be some "compensating developer" type of effect that causes the speed loss. Again the negatives are beautiful, and the curves are smooth. The development times are predictable. What I never knew until now is that I lost some speed.
I just processed 4 sheets of Delta 100 in trays. The community darkroom I visited had old Kodak hard rubber (I'm guessing they're hard rubber) trays, 5x7 size. They worked great.
I got some scratches, I'll have to practice more. The film I shot wasn't particularly important so scratches are OK I guess. I know exactly when the scratches happened; I wasn't careful when shuffling and stabbed other sheets with the edge of the sheet I was re-introducing to the bath. There was also a decent amount of dust on the sheets; I didn't wash my hands before I loaded the holders and I'm using old holders so they are probably grimy. They are light tight though, as is my camera. No light leaks noticed.
I used Rodinal, we'll see how they look once they dry and I have a chance to contact print them.