I don't want to sell anything but last night I was in my darkroom printing. I never did pay attention to that table on the enlarger chassis, next to the coloumn. It has three coloumn (no pun intended!!!), one beta, one 50 and the last 30, and many rows. What the hell is this table? I've guessed that the 50 and 30 refers to the enlarger lens but what about beta? Is this an enlargement factor?