HP5 Plus developed with PMK pyrogreenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread
I have been using PMK using Gordon's Hutchings directions with 35 mm Tri-X and T-Max (100 and 400) for about two years. I have been very pleased with the results. Recently I decided to try HP5 Plus, both 35mm and 120 after reading some of the rave reviews here.
Couple of things puzzled me. I always rinse the film with a couple drops of Edwall LFN before developing. With the 35mm the rinse poured out clear but with the 120 it came out a darkish blue. I was not too perturbed by this since this also happens with the T-Max films. However since the 35 mm and 120 were both HP5-Plus, why should itone rinse come out darkish and the outher clear.
The 35mm turned out well but the 120 negs were very thin. Again same film. I have not printed either fromats yet so can't say anything about print results. Just looking at the negatives both did have fair amout of stain.
-- Mei leng Lau (firstname.lastname@example.org), December 08, 2001
Hopefully the Ilford man will answer your question but for now I can tell you I've used HP5 in both 35 mm and 120 for several years and get the same result. I fill my tank with the correct temperature water for a few minutes to get tank, reel & film all the same temperature before dumping in the developer and the water from the 120 always comes out dark. I understand it's a coating Ilford puts on it to stop the light from bouncing back during exposure. There are technical terms for all this but they don't come to mind right now. Harv.
-- Harv Jenkins (email@example.com), December 09, 2001.
The 120 film has a clear base with an antihalation dye that washes out in processing. The 35 mm has a gray base of density about 0.2 to prevent both light piping past the lip of the cartridge and halation. It doesn't wash out.
-- Patrick A. Gainer (firstname.lastname@example.org), December 17, 2001.
The previous answers are both correct, anti-halaion dye in the 120 format. However, the above answers did not address the 'thin' 120 negs. It's true that 35mm has a much denser base + fog, however the image density should be the same. HP-5+ has an honest EI of 400. I suspect that your exposure of the 120 film is under. It may be an inaccurate shutter, or if you are using different meters with each camera, one (or both!) may need calibrating. BTW, HP-5+ in PMK yeilds a ruler flat curve, making printing much easier.
-- Michael Fraser (email@example.com), December 25, 2001.
The 120 negatives of HP5 are thinner than the 35 mm negatives because the development time for the 120 film is longer in PMK pyro than the time for 35mm HP5. Don't ask me why. My 120 negatives were thin, too, and I thought it was the camera since I use the same handheld meter for 35mm and 120 photography. Then I noticed on the inside of the 120 film box how the development times for HP5 were different if the developer was HC110. Times for other developers were the same in both formats, but the HC110 time was longer in the 120. So I tried a longer time for the 120 in PMK pyro and now the negatives are fine. Again, don't ask me why--same water, same tank, same agitation, same temperature/thermometer, same idiot agitating the tank. For 35 mm at 80 fahrenheit--8 minutes. For 120 at 80 fahrenheit--9.5 minutes.
Lee England Natchez, Miss.
-- Lee England (firstname.lastname@example.org), February 01, 2002.