HC 110 new dilution

[Bob McCarthy]

I use HC110 with Tmax 100 typically at 6 minutes at 68 deg.

Moving to TMax 400 (and 8x10) has me refining the timing and with the switch to tray developing from dip and dunk, I'm thinking I want to slow things down a touch. I've come across the concept on diluting "B" (1/31) to "H" (1/63). I hope I have the letter correct.

Has anyone tried this approach and what were your conclusions, same as "B" at twice the time or...

bob

[Drew Wiley]

I don't think it will be quite that simple. Ran some tests last fall at high dilution and it
affected the contrast as well as the toe of the film quite a bit. Don't want to go into details here because it was a special application test which was successful. All you can do it try is and see what happens. But I was actually plotting the result with a
densitometer.

[Jim Graves]

Bob ... here's an informative link to one HC-110(H) user's methods including times for TMax400 @ 200, 400, 800, and 1600: LINK
And, here's a more comprehensive link to HC-110: LINK

[Daniel Stone]

bob,

I have started using Dil. H as a "compensating"-type developer. I'm still somewhat new(ish) to the LF arena, but being that I like high-contrast situations, but with detail(sometimes not) in BOTH the shadows AND the highlights.

dil. H works for me(after a bit of tweaking) to get what I want.

my standard dev is 510 pyro @1:100 dilution. all developing is done in Jobo tanks on a unicolor motor base.

-Dan

[David de Gruyl]

I don't think it will be quite that simple.

It isn't. High dilution developing depends on how close to exhaustion you bring the diluted chemistry. In other words, both the total amount of developer and amount of film are important variables. If you develop a piece of 8x10 film (which has about the same area as a roll of 135-36) in about 250 ml of solution, this will not be apparent. You will, however, see an impact if you use 1.25 l of solution for that same 8x10 sheet of film.

This has to do with chemical diffusion and equilibrium in the solution, as well as mass transfer effects (diffusivity) at the emulsion interface. Even without agitation, developer attempts to equilibrate in concentration throughout the solution. It takes time, but the higher the base concentration, the less time it takes. [I always feel like I should erase paragraphs like this...]

[here we go again] Some justification for the low concentration (high dilution) chemistry has been made based on "local exhaustion" and the ability of the shadows to continue developing after the highlights have essential reached exhaustion. This only works for a narrow band of decreasing total concentration inside the developing tank. [I almost said reaction vessel... I really should stop writing]. Too little, and you run out of developer, too much and you overdevelop and do not see all of the desired effect. Even when the starting concentration is correct, the slope of the concentration as a function of time is determined by the exposed film area and the initial amount of developer. Assuming you expose your film consistently, you can say total film area instead of exposed area.

By the way, I deal a whole lot more with very low concentration Rodinal than with HC-110 at any concentration. I will probably be combining the two in the near future for some tests, but as of right now I have no useful information on this specific reaction. But, that being said, the theory is the same for low concentration developing. I just can't help with timing.

[Michael Graves]

I am an Ilford user, and I had the same issue. I wanted longer developing times, and Dil. H didn't work. Shadow detail drops to abruptly and contrast was flat. I settled on a 1:50 dilution with developing time increased 50% over Dil. B. I find I like that combination for HP5 better than Rodinal, although I still think FP4 in Rodinal is the best combination for roll film.

[BetterSense]

I use it at 1:50 for no reason other than that's what I use for Rodinal.

[Louie Powell]

I agree that it's not 'simple' - but I've been using dilution H for a number of years and it seems to work just fine for me.

I use EFKE 100, rated EI50, and process for 11 minutes at 68 degrees with intermittent agitation using a 6-sheet slosher in an open tray.

[Drew Wiley]

Thanks for pointing that out, David. In my tests I used two liters of solution for only
four sheets of 8x10 film, plus an anti-fog restrainer. That's why my results were so
predictable. Insufficient solution volume in high dilution is just looking for trouble.

[Bob McCarthy]

I'm using 2 liters of working solution, processing 4 to 6 sheets of 8x10 one shot. Hmmm I wonder if H has enough capacity. Where the kodak tear sheet. I know I'm ok at B, I doubt I am with H unless I go to 3 to 4 liters of working solution.

Thanks for the links.

Bob