Rodinal dilution/exhaustion

Somewhere I saw data for Rodinal about how much developer was needed per square inch of film.

My new Nikor 4X5 drum holds 36 oz., and I develop at a dilution of 1:100. The drum holds 12 sheets of 4X5 (240 sq.in)

I'm trying to figure out if I am stretching out the possibility of Rodinal exhausting itselm at 1;100
and if I need more solution, or to cut back to running only six sheets per 32 ozs.

Anybody remember seeing this data on Rodinal needed per sq inch of film. I CAN'T REMEMBER!

Thanks in advance for any help.

Richard: I did some testing a long time ago, I was using a 1:50 dilution. My impression was that I could develop 4 sheets of 5X7, then dump it and remix to avoid exhausted developer. So my guess is you're in trouble since that would be only 140 square inches in twice as strong a dilution. I am reasonably sure I have the data sheet which came with my last bottle of it (which may or may not be my last bottle of it...) and if that information is there I will supplement. I am sorry I can't be more definitive, but I believe I decided on the 4 sheet max with 5X7 film by experimentation.

Looking at page 6 of

this document

shows for Rodinal Yield "One-shot developer: with 500 ml concentrate about 50 films (135-36 or 120 roll film) can be developed." That works out to 10 ml of concentrate per 80 square inches of film.

There are those who will say much less concentrate is required, but successfully taking that route depends on average image densities being such that exhaustion is avoided. Absolutely predicatable results regardless of image makup demands the specified minimum concentrate. You can, of course, choose to rely on luck...

PS: That works out to around 5 (not 6) 4x5 sheets in 36 (not 32) oz. of 1:100 working solution.

Richard, you should be fine -- you've got the equivalent of 3 rolls of 120 or three 8x10 in that tank, and that gives you what amounts to 12 ounces (about 360 ml) of developer per roll. Although Agfa recommends 10 ml of concentrate per roll, I've read reports from many users who find it works just fine at 1:100 with 35 mm film in a single reel tank, which is 8 ounces (240 ml) per roll; you have 50% more developer per square inch than that.

BTW, FWIW, those tanks will also accept two large diameter stainless reels that hold a roll of 220 with the same wire size as common stainless 120 reels; I've got one that has two 220 reels, but unfortunately not the sheet film cage. I don't use it any more, since finding my Paterson will not only accept 220, but will let me load two 120 rolls sequentially, and develop them in 500 ml of soup. I keep watching eBay for the 4x5 cages without the tank, but the last one I saw went over $100, which was more than I could spend at that time.