HC-110greenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
I am developing tri-x and tmax fills (not together ;), using HC-110. I have a couple of questions. First, although I ordinarily use 120, i do have a 220 back and recently have developed 2 rolls of 220 using the same process. Do I need to increae the potency of the developer solution (or development time) since there is more film surface area? If so, is there some way to figure out by how much other than trial and error. Also, I have been mixing one part HC-110 to 28 parts water, and not using a stock solution. It seems to work fine for me, but I'm really just a beginner. Is there any reason that I may be overlooking that this is not a good idea? Seems to me like it would yield more control not less (assuming accurate measurement of 1 oz., which isn't too hard with the right tool) gien that i start each time with fresh HC-110 and not a stock that has been sitting around for some months.
Last, does anyone know where I can find the characteristic curves of most black and white films. I am looking for a single source, and maybe even one that compares the curves to one another and explains what the difference in result theoretically should be. In my experience, these curves don't come with the film and I couldn't find such a book at B&H.
-- che baby (email@example.com), February 15, 2000
I have been using HC-110 mixed from the "syrup" for years with good results. I use a dilution of 1 part syrup to 31 parts water. I use the mixing water to rinse the small graduate that held the syrup to make sure it all gets dissolved, then top off to the final volume.
I have processed two 36 exposure 35mm rolls at a time in a 1 pint tank with that mix and had good results. I think 1 roll of 220 will have about the same surface area, so I dont think any adjustment would be needed.
As for published curves, probably Kodak would be the place to look. Yours will vary according to your agitation procedures, time, etc. I dont know that I would be all that worried about it. I have simply tuned things by finding development times for 3 basic lighting situations until they print on a normal paper grade (I dont use multi-contrast papers) with my enlarger or contact printer and then try to repeat as carefully as I can.
-- Tony Brent (firstname.lastname@example.org), February 15, 2000.
Tony, thanks, my question then is what if I want to develop two rolls of 220 at once given the same developer volume, what adjustment to developer strength or development time might be required? In other words, I have a 32 oz tank and the 220 reels are the same size as the 120 reels, and I want to be able to do 2 at once for purposes of efficiency, I just don't know what adjustment to make. And also, do I need to fix for longer?? thanks.
-- (email@example.com), February 16, 2000.
You shouldnt have to change anything. The only differenbce is that you are mixing up twice as much VOLUME of solution, but the dilution is the same. For instance, when I use my 1 pint tank, I mix 1/2 Oz of syrup to 15 1/2 Oz of water, and when I use the larger tank I mix 1 Oz to 31 Oz. The strength of the dilution stays the same. If you start changing the dilutions, you will run into strange results.
The rule of thumb for fixing is twice the time it takes the milkiness to clear.
-- Tony Brent (firstname.lastname@example.org), February 16, 2000.