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.
I only do 4 sheets of 8x10 at a time in an oversize tray. Have to be very careful not do get any
surge marks on this kind of subtle very low contrast work. Two problems with exposure. You have
to balance the mask for the depressed green sensitivity of the FP4 pan film, and you have to null
out the effect of the orange mask. After considerable testing what works best for me is to balance
the color head to 5000K or thereabouts using a color temp meter, then add a light YG filter (Hoya
XO) to cure the pan effect, then a pale orange (G) to "see through" the mask density. But color
balance can change with recip effects, so I aim for about a 10 sec exp under the enlarger in the
I appreciate the tips. I will be in San Francisco this coming March for the national conference of the Society for Photographic Education and would love to visit your lab and talk with you in person about masking for color negatives if that is OK with you.
I'd be happy to give to a demo Greg, but it's still too far away to know what my travel schedule will
be like in March, so just email me a couple weeks in advance. Seeing how this is done in person is
indeed more useful than an entire volume of notes.
Thanks, I'll stay in touch.