Ah, okay, context got lost.
Yep, I see Braxus used 4:30 and I've have gotten ~5.6 (= 5:35) -- which is about 15% difference, and quite probably photographically significant difference. Might well be that the figure of 4% per degree F or 7% per degree C varies with different developers, since most have more than one developing agent and different agents might have different rates of activity change with temperature (for instance, hydroquinone in a multi-agent developer becomes nearly inert in terms of developing action below about 16 C, leading to a sudden, sharp increase in required time below that temperature).
I can only say I've used my method (with Fahrenheit thermometer) at darkroom temperatures up to around 90 F (34-35 C) with results reasonably comparable to "normal" 68F/20C process at published times. Most of the developing I did at that temperature, however, was with Parodinal, a single agent developer; dual- or multi-agent chemistry might well have a more complex response.
Yep, I see Braxus used 4:30 and I've have gotten ~5.6 (= 5:35) -- which is about 15% difference, and quite probably photographically significant difference. Might well be that the figure of 4% per degree F or 7% per degree C varies with different developers, since most have more than one developing agent and different agents might have different rates of activity change with temperature (for instance, hydroquinone in a multi-agent developer becomes nearly inert in terms of developing action below about 16 C, leading to a sudden, sharp increase in required time below that temperature).
I can only say I've used my method (with Fahrenheit thermometer) at darkroom temperatures up to around 90 F (34-35 C) with results reasonably comparable to "normal" 68F/20C process at published times. Most of the developing I did at that temperature, however, was with Parodinal, a single agent developer; dual- or multi-agent chemistry might well have a more complex response.