hc-110 dilution

[pierre_robitaille1]

I have made all my zone system tests of tmax100 4x5 using dilutions of 1:15 (from stock) for n, n-1, n-2 but when it came to n-3, the development time became very short (under 5 minutes) so i changed the dilution to 1:30. the results are ok but development time is exceedingly long. is there a formula to compute development time for various dilutions?

[alec1]

Check here: http://www.covingtoninnovations.com/hc110/

[neil_poulsen1]

Within an appropriate range, concentration is inversely proportional

to development time. If one doubles the concentration, one must halve

the development time to achieve the same effect. Below a minimum

level of concentration, I suspect that this relationship no longer

holds.

[scott walton]

You development times shouldn't be that long. Short with Dilution A,

yes but with Dilution B (1:31) you should be in the 8-10 minute mark.

[charlie_strack]

Dilution B is 1:31 from consentrate, and 1:7 from stock. 1:15 from

stock is half the concentration of dilution B. 1:30 from co

 

<p>

 

Are you certain you have enough developer that you aren't going into

developer exhaustion?

 

<p>

 

Kodak gives capacity as 5 or 10 sheets per liter dilution B (first

number is tank, second is tray processing) which gives 2.5 or 5

for "half B" and 1.25 or 2.5 for "quarter B" dilutions. These are

8x10 sheets.

 

<p>

 

My impression is that it is very difficult to get good results with

such extreme contractions from modern film. If you don't have it, I

suggest you get the book: Film Developing Cookbook.

[pierre_robitaille]

I want to thank you guys for your quick answers. alec, the site you

suggests contains a lot of useful info. neil, do you know what is

that minimum level of concentration for hc110? scott, my normal time

is 6 minutes at 68 degrees. charlie, that is a good advice and i

always have to double check the capacity, especialy at greater

dilutions. as for the capacity of contraction of modern films,

tmax100 is very, very sensible to variations of development times and

temperature. i always use rather large volumes of developper (at

least 64 ounces) in a water jacket to keep constant temperature.