Having first learned B&W processing with D-76 and Dektol back in days of yore, I remember clearly the instructions for mixing them at 125 and 105 degrees F, respectively. When I switched to D-23 several years ago, I followed the published instruction (Adams and others) to mix at 125. More recently, having used up my last Permawash, I have begun using sodium sulfite (with a seasoning of bisulfite) for wash aid and noticed that it mixes perfectly well, apparently, at processing temperature, 68-70.

Having seen various recommendations to simply mix D-23 fresh at processing time (an attractive approach for consistency), but having always avoided this, due to the extra cooling time required (yes, I know about ice-cubes; not convenient to store in my situation), I began to wonder: If the sulfite dissolves at room temp, how about Metol?

Just now I tried a little experiment. In 1 1/2 oz of 75-degree water, I dissolved a pinch of Metol, apparently successfully, in about a minute. I added a bunch of sodium sulfite and found that this, too, dissolved without much ado. Not to strict proportion, I understand, but in that direction.

Therefore, my obvious question is, am I missing something here that is not visible but will affect the processing properties if I mix my D-23 at about 75, which will be much, much quicker for me to cool down? Is it not really mixing as well at this temp? Does the high temp affect the chemical properties in some way? Or, perhaps, is teh hig temp actually needed only for other components of developers such as D-76