intermittent agitation

[BetterSense]

Every film datasheet I have read suggests intermittent agitation for small tank processing.
Is this because intermittent agitation is actually better than agitating continuously, or just because it is more convenient? If continuous agitation were just as easy for me, would the film engineers tell me that it was inferior to intermittent agitation?

I have never seen any film datasheet suggest minimal or no agitation. They always suggest a minimal amount of agitation. Extrapolating, does this mean more is better, so long as I control contrast?

 

[Jager]

Assuming you could control contrast and density within a continuous-agitation process, I'd guess the benefit of intermittent agitation would remain convenience. I know I, for one, would not develop film in tanks if it required constant agitation. That would quickly drive me batty.

An automated constant-agitation regimen, a la Jobo, is different story. And, of course, there's plenty of good data on that.

 

[MattKing]

Ever tried to use continuous agitation without either a motorized processor or, at least, a hand operated roller?

If you had, you will know one major reason why intermittent agitation is one of the recommendations.

Kodak, for their part, provide data to those who use motorized continuous agitation.

If you don't agitate at all, or use very little agitation, the development isn't uniform, due to local developer exhaustion.

Sometimes that unevenness is quite subtle - leading to little more than enhanced edge effects - so minimal agitation can be a useful tool when employed carefully, and with knowledge aforethought.

Too much agitation can lead to increased contrast, more obvious grain and developer oxidation. Developers are designed with a certain amount of agitation in mind. Why waste all the work that went into that design?

 

[Gerald C Koch]

There is also a danger of surge marks from continuous agitation. These are caused by fresh developer following the sane path around the film. The fresh developer causes greater development at those points. There is also the loss of edge effects from developers that produce them.

 

[Xmas]

The agfa daylight tanks require agitation every few seconds. The film is not covered by liquid.
Lots of people use stand