It is important to keep the temperature of the chemicals close to the same. Temperature shock can induce reticulation, as mentioned above, though not as likely with modern films. More importantly the temperature shock can increase the grain size. (I think it induces increased clumping.)(posted 8738 days ago)If you need to process using high temperatures, there are specific high temperature developers which might be useful. Also, PMK is supposed to be OK to 85 degrees F, according to its designer.