Short on Exposure?
I remember working in a downtown area that had heavy electrical motors kicking-in every 10 to 20 minutes or so. I also hade two of the old oil capacitor Solar stabilizers to keep the voltage constant. Nevertheless, fluctuations still occurred (B&W) in batch printing that drove me nuts. I was processing 100 prints at a clip in baskets in a jacketed 20X30 nitrogen-burst tank processor. I knew the bulbs were fluctuating intermittently and I was loosing an unacceptable number of prints. After trying everything else, I simply increased the exposure time (3x). It took longer to expose the prints, but I didn't lose any prints and repeat batches were consistent. Since you are tray processing, if your problem is traceable to voltage fluctuations, try increasing your exposure time until the observable fluctuation is less than a third of a stop (voltage fluctuations are time/intensity dependant). Any remaining difference you can control in the tray. In small batches, it is always better to use fresh developer and fresh developer is always 'hot', but remember, if you let Dektol set (even a few days) is will oxidize and give observably different results (lower contrast, increased developing time). A good control test to solve the problem is to expose a strip of your paper without any negative in your enlarger (make sure its focussed correctly) and vary the exposure until you achieve about a 25% uniform gray (don't tear the paper, cut it with scissors).Expose about 25 small strips in this fashion and store them with your unexposed paper. Prior to each new printing session, process an exposed strip and adjust (if necessary) your processing (or exposure) times accordingly. The rest is simple.
Originally Posted by geraldatwork