A question now about agitation and the formation of edge effects with general purpose developers. Of course generalizations are difficult if not impossible, but still.
Anchell/Troop take the view that generally speaking a rest period of 30s between agitation cycles is too short. One minute is the minimum, and longer rest periods result in greater edge effects, and continuous agitation essentially prevents them altogether. On the other hand, edge effects are supposed to be the product of diffusion within the emulsion layer. In Richard Henry's tests, he found continuous agitation, 20 second rest intervals and 1 minute rest intervals produced the same edge effects. Unfortunately he does not go into much more detail on that, and he did not investigate longer rest periods (3 minutes is a common recommendation for maximizing edge effects with non-solvent compensating developers).
What are your thoughts on this? Clearly many variables are involved, but are edge effects as sensitive to agitation as we assume they are?