Minimum HC-110?

[Doc W]

This came up again in another thread (and I am sure we have been through this before - I just couldn't find the thread). The question is: how much HC-110 is required per sheet of 4x5? Here is how I calculated it, basing my numbers on the Kodak data sheet ([url]http://www.kodak.com/global/en/professional/support/techPubs/j24/j24.pdf[/URL])

Kodak says that 1 litre of dilution A (1:15) will develop five sheets of 8x10 in a tray (it is twice as much for a tank, but let's stick with the tray capacity for now). That would mean that 200ml of dilution A would be required for one 8x10 sheet. This amount of dilution A would contain 12.5 ml of HC-110 (200ml / 16).

So if one sheet of 8x10 (80 square inches) requires 12.5 ml, then one sheet of 4x5 (20 square inches) would require 1/4 as much, or 3.125 ml. I round that up to 4 ml to be on the safe side.

With tank development, a litre of dilution A can development twice as many sheets, so we can just halve the amount to 1.5625 ml, say 1.5 ml.

I am not good at math or even basic arithmetic, but I think I did that right. How does it sound?

I don't really understand the difference capacity for tray versus tank, and I don't know how one would calculate this for a rotary processor. For my Jobo, I use between 3-4 ml per sheet of 4x5.

 

[frank]

For what it's worth, i develop 5 rolls of 135 (or 3 rolls of 120 film) at a time in HC110 diluted to 1:100. That's 15ml developer in 1500ml of water.

 

[Gerald C Koch]

One difference between tray and tank is that tray developer is constantly exposed to the air and more prone to oxidation. Developer in a tank is essentially a closed system.

I typically use a 1+49 dilution which would be a 5 ml minimum for a single roll of 35 mm.

 

[StephenT]

I think 3ml minimum for a single sheet of 4x5. I would stick to what you are doing now with 3-4 ml in your Jobo.

 

[MattKing]

I would definitely use the tank capacity numbers, rather than the tray numbers, for a comparison when using a tank.

Even if you are using a rotary processor.

In addition to the differences in oxidation, it seems to me that the effects of more complete agitation that one acieves in a tank are likely to increase capacity.