HC-110 dilutions

[Ed Pierce]

Has anyone ever seen published a table showing development times to achieve the same degree of development in various dilutions? For example, if my N time for Tri-X is 8 minutes in dilution B, how long would it take in dilution E? I'm running my own tests but am curious to know what others have found. Thanks

[Jon_2416]

One of the best HC-110 resources:

http://www.covingtoninnovations.com/hc110/index.html

[phil sweeney]

Ed: here is a little info, may be helpful for some non-standard dilutions: http://home.att.net/~shipale/timeandtemp.html

[Robert C. McColloch]

When I was tray developing, I found that approximately 5 minutes in HC110 Dil B was to short a time to get uniform development. I found through testing that I could double the developement time by using a 0.846% solution of HC110 concentrate.

[Eric Rose]

Last time I looked the Great Yellow Father had all that info on their website, but it has been awhile.

[bob moulton]

A text used for college photo classes, labeled Photography, Author Chas. Swindlund (SP) contains a good chapter on testing films and using dilution, not time, for determining +n- times. The examples used are for HC-110. You might get a copy of the book and examine it. I believe Swindlund terms this using a "density parameter curve." One can adapt it for those developers capable of such dilutions. I've used it successfully with FG-7, in the sodium sulfite dilution and also with TMaxRS, using dilutions 1:4;1:7,1:9.1:11, and 1:15.

Bob Moulton

[Bruce Watson]

If you can't find it published (and Covington's web site probably has what you need), you can get a starting point by understanding the chemistry and the math.

I'm not going to give you a chemistry or math lesson here (to everyone's relief!) but it basically devolves down to this. If all other things are held constant, when you double the dilution of the developer (say, from dilution B (1:31 syrup) to dilution H (1:63 syrup)) you multiply your development time by the square root of 2. So... 8 times 1.4 is what?

Just knowing that the relationship between development time and dilution is ***not linear*** should be a big help in approximating a place to start testing from, I think.