Quote Originally Posted by albada View Post
The OP is proposing using a fixed number of agitations instead of a fixed time-interval.
My knowledge of chemistry is rudimentary, but this makes perfect sense to me.
If a chemical reaction only proceeds half as fast and thus takes twice as long, then doubling the time-interval (giving the same number of agitations) will produce the same result as double-speed and half-interval.

However, the rate of diffusion through gelatin does not depend on dev-rate, so that complicates things.

Anyway, I have created a concentrate giving XTOL-quality, and I designed it to have twice the dev-time as XTOL. And I recommend agitating every 60 seconds instead of Kodak's recommendation of every 30 seconds. It's worked fine in my experiments.

Mark Overton
Mark,

Just a couple of thoughts here:

First, the time between agitations is long enough to allow the developer to exhaust in areas of greater density (compensation) should be fairly constant for a given film/developer combination.

Now, if you want a compensating effect, you need to make sure the time between agitations is long enough. It would seem to me that this time would be longer with a more active developer than with a less active/weaker one. Therefore, to achieve a certain amount of compensation, one would have to increase the agitation intervals for the more active developer, not decrease them as the OP is suggesting.

Similarly, for weaker developers, the interval at which a certain amount of compensation occurs will be shorter. Therefore, for a given amount of compensation, one would have to increase the frequency of agitation compared to a more active developer, not decrease it.

Of course if you don't want and compensation, then just agitate away, it shouldn't make much difference at all as long as the agitations aren't long enough for developer to exhaust in the highlights; any agitation scheme that accomplishes this would yield the same results as long as development time was appropriately adjusted.

Best,

Doremus