Greg - you will obviously have to fine-tune things to your own workflow, but my formula for basic
contr masks FP4: Mix HC-110 to "stock" 1:3. Add 20ml of 1% solution of benzotriazole (more predictable weighing out tiny amts of powder). Then dilute this down 1:31 for use (note: this is 1:31
from STOCK, not from concentrate). Try 10min at 20C. The final mask should be quite weak, with
a DMax rarely above .30, yet a tiny bit of density even in the shadows; otherwise you risk crossover
. Exposure and interpositives are a bit more complicated. I'll do a followup post in a bit.