During normal development you agitate once every thirty seconds or once every minute. That insures a fresh supply of active developer in contact with the emulsion.
When you reduce agitation, the fresh supply of active developer works longer in the same area of the film. The highest activity of the developer is in the highlights, as that is where density of silver eventually will be highest.
So, relative to how high the density is in a specific area of the film, the developer exhausts and slows down or stalls development - in that particular area. That means that a scene with very bright highlights will receive an extremely compensating form of development, and that a dimly lit scene can get a boost, all based on developer exhaustion.
Now think of contrast - what is contrast? Difference in brightness in two adjacent areas. Since the developer is mostly active where it doesn't have to work so hard, you can get some interesting effects where fresh developer 'creeps over' from a less dense to a more dense area. This can cause an edge effect that appears to increase sharpness and local contrast. It really is pretty cool to watch and can be quite beautiful in some instances.
I hope that helps in understanding the concept of extreme minimal agitation.
Originally Posted by Daniel Jackson
"Often moments come looking for us". - Robert Frank
"Make good art!" - Neil Gaiman
"...the heart and mind are the true lens of the camera". - Yousuf Karsh
Don Cardwell's lucid description of how XTOL can be used to boost the "speed" of FP4+ has got me thinking. My current 35mm film is HP5+ rated at 200 and developed in ID11 1+3 for sunny days. Great for hand holding, with orange filter, at around f8 at 125th. I am happy with the prints from these negatives, but could always do with extra sharpness for when I want to make bigger prints.
Could I switch to FP4+, rated at the same 200 speed, developed in XTOL as Don outlined, and be able to make sharper ( or bigger ) prints with good tonality?
The easy answer is to just develop as normal. Your "actual" EI for FP4 could be as high as 200, and your "actual" EI for HP5 could be as low as 200. Who knows unless you have tested. At any rate, with some printing skill, you can probably get usable shots just developing as normal.
You could then intensify the negs with the intensifier from Photographer's Formulary, if needed. It is actually rather affordable.
The next easy answer is to just assume box speed for FP4 and do a simple push. You exposed 125 at 320. That is 1-1/3 stops under. It could be worse! Your shadows and midtones will be darker than normal, but you can develop for either more time or with more frequent agitation to make the high mids and highlights look normal. With good printing skill, etc., etc.
The hard answers come when you start wanting to rescue as much of your shadows as you can. In this case, you might want to employ a developer that typically reinforces a film's speed. X-Tol, for instance, or perhaps T-Max.
Then, you can use less frequent agitation to reinforce those shadows even more.
Personally, what I would do is combine a push with less frequent agitation. Sounds counterproductive, but it works quite well.
Also, I would personally test a roll (or two) first, if the shots were really important to me.
Expose another roll of FP4 at 320, in as close to the same lighting as possible, including flash, if that's what you used. Mix up some X-Tol or T-Max (or Ilford equivalents). Cut about 1/3 off of your roll and develop it normally. See how it looks. Proof the frames to see what you can get them to look like. Next, cut another 1/3 and try a simple push to see what the results are. Proof, etc. Next, try the last 1/3 at 3x normal development time, but agitation half as often as you did with normal development. Proof, etc. If you shoot more test rolls, you can do more tests!
Oh...and do it all at 75F to reduce the time! I do everything at 75F anyhow, except for Efke.
Good luck. You're not as bad off as it sounds.
Last edited by 2F/2F; 07-24-2008 at 02:41 PM. Click to view previous post history.
"Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."
- Rob Tyner (1944 - 1991)
Thanks for all the suggestions, everyone.
The test roll looked good in XTOL, with a straight push as well as with 1+1 and 1+3 dilution / semi-stand techniques. I went with 1+3, 19 minutes semi-stand @ 20°C for the "real deal." (Mostly because I had the right amount of XTOL for that dilution sitting in the bottom of a bottle after the tests.)
I'm pretty sure this roll would have been quite printable without any push, but I learned something more about processing technique so I'm happy. ^_^
I've also got a second developer to play with now. (Was using strictly TMax before, for convenience.)
Now to catch up on printing... Ugh...
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