I should have added to my note about Rodinal and Tri-X that this combination gives an Exposure Index of 400. The above formula is for normal contrast negatives. You can lower contrast by changeing the dilution to 1:85, or increase contrast with a dilution of 1:50. Development time remains 11min. 30sec. @ 68 degrees. For an Exposure Index of 800, dillute 1:50 and increase development to 15min. @ 68 degrees.(posted 9348 days ago)