Rodinal dilution and acutance

I have heard it both ways, that higher dilution (i.e.: 1+50) = higher acutance; and that lower dilution (i.e. 1+25) = higher acutance.

Does anyone know which is correct?

pstake said:

I have heard it both ways, that higher dilution (i.e.: 1+50) = higher acutance; and that lower dilution (i.e. 1+25) = higher acutance.

Does anyone know which is correct?

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Rodinal is a high acutance developer and I would suggest the only difference in dilution strength is that the longer times provide greater possibilities for still bath development, but doubt if this makes much difference.

more of a compensation effect, although semi stand and stand development with 1:100 do indeed increase adjacency effects and makes mackie lines broader and deeper!

Rodinal at 1:25, especially using Agfa's recommended development times, results in contrasty negatives. One can mistake high contrast for accutance. A properly developed negative using dilutions higher than 1:50 (1:75 and 1:100) produce edge effects enhancing sharpness. The effect is visible but not dramatic. One could argue changing film from Tri-X to FP-4 or T-Max 100 is nearly as effective.

Richard Jepsen said:

Rodinal at 1:25, especially using Agfa's recommended development times, results in contrasty negatives. One can mistake high contrast for accutance. A properly developed negative using dilutions higher than 1:50 (1:75 and 1:100) produce edge effects enhancing sharpness. The effect is visible but not dramatic. One could argue changing film from Tri-X to FP-4 or T-Max 100 is nearly as effective.

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Thanks for this. Thanks to everyone else, too. Good information.

+1 on pstake's reply.
Long development times with high dilutions (a favorite is 1:100, from 20 minutes and up depending on agitation schemes - stand, semi-stand, etc) yield acutance effects.
The smaller the format size, the more they are seen in the print.
You can find more on this forum by searching for "stand" and "semi-stand", many threads gone over the dam.

George Collier said:

+1 on pstake's reply.
Long development times with high dilutions (a favorite is 1:100, from 20 minutes and up depending on agitation schemes - stand, semi-stand, etc) yield acutance effects.
The smaller the format size, the more they are seen in the print.
You can find more on this forum by searching for "stand" and "semi-stand", many threads gone over the dam.

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One more question. What is the difference between "stand" and "semi-stand," or is it the same thing?

Stand development is a principle that involves initial agitation (longer than normal, some recommend up to 2 minutes), then the tank sits for a much longer than normal time. (not for open tray schemes) Semi stand is similar at the beginning, but introduces agitation at intervals of 3 - 5 minutes, to ensure uniform development in even (eg - sky) areas.
I have left a lot out here - use the search engine for this forum, and enter the two terms "stand" and "semi-stand". you'll find lots to read, opinion and fact both. People have widely varied experiences with this method.