Yes, all true! If you are doing production, you can save time and chemicals by heating the sulfuric to something like 90-100 degrees and then put a LITTLE bit of hydrogen peroxide in it at the time you put in the wafers. Ammonium persulfate works even better. BE CAREFUL! Consult your safety people. Wear safety equipment! You do not want this stuff on your person! If the resist coating is quite thick, the wafers may want to float out of the etch baskets. You might want to experiment with dummy wafers before risking important ones. Roger Brennan