For my next pinhole outing, I want to have longer exposure times using Acros. At box speed, I get 1-2 seconds, which is a bit marginal for keeping things stable when operating the shutter in my pinhole camera (a bit of thin wood that slides in and out of a slot). A bit of shake or mishandling could be a fair proportion of the overall exposure time. At 4-8 seconds, the proportion of time that might have shake reduces quite a lot. I'd also like to introduce some subject motion blur if the opportunity presents itself.
I'm interested in rating the film at 25asa, with the aim of getting negs that will scan okay in my Epson V700. I'd appreciate thoughts on whether my plan for developing is likely to work.
The film is 120 format, so 600ml of solution, and the developer is HC-110. I'm thinking of using this quite dilute to get a reasonable development time - in dilution B at 100asa, Acros is developed for 5.5 minutes with inversions at 1 minute intervals. On the other hand, a dilution of 1+99 means 6ml of concentrate which is about the limit for the developer not becoming exhausted. Adjusted for 1+99, the time for 100asa becomes about 17 minutes.
To pull to 25asa, about all I have to go on is some times from the Massive Dev Chart for 100asa and 50asa. For Acros in Rodinal: 13.5 mins at 100asa, and 11 mins at 50asa, and Ilford Delta 100 in HC-110: 6 mins at 100asa, 5 mins at 50asa. In other words, a ballpark guide to pull one stop is to develop for about 80-85% of the time.
I have two questions...
To pull another stop, do I reduce the development time by the same percentage a second time? In other words (rounding for easy minutes), 80% of 80% (=64%) of 17 minutes gives 11 minutes.
If that's about right, would normal agitation be okay, or should I consider less agitation to hold the highlights? Every 2 minutes? 3 minutes?
I'm interested in rating the film at 25asa, with the aim of getting negs that will scan okay in my Epson V700. I'd appreciate thoughts on whether my plan for developing is likely to work.
The film is 120 format, so 600ml of solution, and the developer is HC-110. I'm thinking of using this quite dilute to get a reasonable development time - in dilution B at 100asa, Acros is developed for 5.5 minutes with inversions at 1 minute intervals. On the other hand, a dilution of 1+99 means 6ml of concentrate which is about the limit for the developer not becoming exhausted. Adjusted for 1+99, the time for 100asa becomes about 17 minutes.
To pull to 25asa, about all I have to go on is some times from the Massive Dev Chart for 100asa and 50asa. For Acros in Rodinal: 13.5 mins at 100asa, and 11 mins at 50asa, and Ilford Delta 100 in HC-110: 6 mins at 100asa, 5 mins at 50asa. In other words, a ballpark guide to pull one stop is to develop for about 80-85% of the time.
I have two questions...
To pull another stop, do I reduce the development time by the same percentage a second time? In other words (rounding for easy minutes), 80% of 80% (=64%) of 17 minutes gives 11 minutes.
If that's about right, would normal agitation be okay, or should I consider less agitation to hold the highlights? Every 2 minutes? 3 minutes?