dev temperature vs contrast

I just finished reading a book by French author Philippe Bachelier, where he says that higher dev temperatures give film more contrast.

On the other hand, I remember reading in "Edge of darkness" (specifically when talking about perceptol 1+3) that development is equivalent when time is corrected for higher temperatures (shorter time, that is).

So, if I use higher temperatures for development and correct time, do I get an equivalent negative or a negative with more contrast (or somehow different)?

Both are right in a way.

Certain types of developer, particularly MQ (Metol/Hydroquinone), don't work well at low temperatures, below 18°C, and the results are flat lifeless negatives.

However in practice nearly all developers can be used between 20°C-30°C just adjusting the time to compensate for changes in temperature, the coefficient/amout of change is not the same for all developers.

Ian

I always worked with the assumption that development is equivalent when corrected for time. So far, I haven't seen anything that would contradict that assupmtion. However, I would imagine there are exceptions to the rule.

The only exceptions when, as Ian points out, some developing agents are inactive at cooler temperatures.

Bachelier and Thornton were talking about the same thing, but to different purpose.