Agitation question

[behyer]

10 seconds to start, 5 seconds every 30. If you invert a couple or three times and rap it once or twice to knock bubbles loose, that'll take about 5 seconds. Most people never have air bubbles, but if you skip rapping the tank, you'll get air bubbles on only the best images of the roll, and only on the best roll of the batch.

 

[Roger Hicks]

Ok for your delectation:

Here is a graph from Kodak Research (Theory of Photographic Process C.E Mees) showing zero agitation and up to 4 brush strokes per second (close to continuous). . . ]

Thank'ee very much indeed. My reading is that this shows quite clearly that any[/ I] agitation is very different from no agitation, and it's also intriguing that we're looking at very short development times. And, after 1/2 stroke per second, beyond density 1.3 or so, density and contrast appear to increase together, rather than independently.

I think I have a copy of Mees somewhere, so I can read it up further. Once again, thanks.

Cheers,

R.

 

[Roger Hicks]

10 seconds to start, 5 seconds every 30. If you invert a couple or three times and rap it once or twice to knock bubbles loose, that'll take about 5 seconds. Most people never have air bubbles, but if you skip rapping the tank, you'll get air bubbles on only the best images of the roll, and only on the best roll of the batch.

Ah! the laws of nature will not be contravened...

Cheers,

R.

 

[sevo]

So what about development to completion then? would it all level out given enough time and produce a dense but uniform negative ?

I think it would, for (perhaps hypothetical) strictly non-physical developers. With physical and staining developers, YMMV - once there are several competing reactions, any parameter change may shift their balance.