<p>the temp changes the developers activity... higher temp more active, more contrast. Lower temp, lower contrast. Altering time based on temp compensates for the temp based activity change.<br>
Overdeveloped film can have highlights (the dark areas on neg) with no detail. Under-developed, the tones may not have enough separation. If you over develop too the point that your highlights have no detail, there's nothing you can do to recover when printing. Different grade paper (or using VC paper and filters) allows you to 'rescue' the situation somewhat but the range is limited (grades 0-5, less if using a colour head). <br>
Remember that shadow detail is controlled by exposure... highlights controlled by development...<br>
So, Expose enough, and develop just enough...</p>
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