Calibrating for FB and RC paper In Ilford multigrade developer. I use a Durst M601
with colorhead but it is always on white light. I change grades with ilford filters. As is described i calibrated for speed first, but even the RC paper gets me values ranging from -14 to -26, in grades 2-5. For Forte FB paper the speed for grade 2 was okee but the contast level had to be changed from 80 to 145! I have the enlarger head adjusted for 30x40m prints (cm)