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I was sitting in my comfortable chair reading Todd-Zakia Photographic Sensitometry tonight, and re-read the part where the purpose of agitation is described as it relates to standard processing for sensitometric testing.
To paraphrase...
Agitation has nothing directly to do with the diffusion that takes developer into the emulsion and byproducts out of the emulsion. But it does maintain the quality of the thin layer of developer immediately next to the film. The problem of agitation is that a thin layer of developer is adsorbed to the surface of the film and held by an appreciable force.
To remove this adsorbed layer requires vigorous agitation and considerable effort.
As I looked over this thread, most comments minimized the importance of agitation. If you are practicing stand processing or divided development, then deliberately less agitation is the idea. But most of the time, I'd think vigorous agitation would be the best plan.
To paraphrase...
Agitation has nothing directly to do with the diffusion that takes developer into the emulsion and byproducts out of the emulsion. But it does maintain the quality of the thin layer of developer immediately next to the film. The problem of agitation is that a thin layer of developer is adsorbed to the surface of the film and held by an appreciable force.
To remove this adsorbed layer requires vigorous agitation and considerable effort.
As I looked over this thread, most comments minimized the importance of agitation. If you are practicing stand processing or divided development, then deliberately less agitation is the idea. But most of the time, I'd think vigorous agitation would be the best plan.


