What are PMK and Diafine?

greenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread

Apparently I'm out of date. What are PMK and Diafine? Are they available mixed? What do they do to effective film speed?

-- Bill Mitchell (bmitch@home.com), October 05, 1999


I can speak for Diafine. Diafine is a two solution developer that can be used with most any film. It comes in two cans of powder that need to be dissolved in water. It's primary feature is it's consistency of results independent of time, temperature and agitation. As long as the solution temperatures are between 70 and 85 F, developing times in each solution are between 3-5 minutes and agitation is once per minute for 5 seconds, the results are very consistent. Film speeds are typically boosted 1/2 to 1 stop, per the instructions.

You can not do N+/- development with Diafine. My experience is with Tech Pan, T-max 100 and HIE so far. The negatives have a full scale and the results with Tech Pan are the best in 10 years of Tech Pan use. With Tech Pan, you must develop in the "B" solution for exactly 60 seconds. Other wise, temp, time in the "A" solution and agitation are the same.

I discarded Microdol, Ethol TEC, Rodinal, Technidol, and T-max developers last year and am casting my fate with Diafine for all B&W development.

I got a first prize last week for a HIE print souped in diafine and the judge commented on the beautiful range of tones in the print. Many consider Diafine a meat-ball type of developer, but so far I'm extremely pleased with the results. I've develop almost all types of B&W film in almost every developer (including some home brew) over the last 45 years.


-- Gene Crumpler (nikonguy@worldnet.att.net), October 05, 1999.

Gene, I've looked at your web page--you do very nice work. You obviously know what you're talking about, I'll give it a try. I've always found developing Tpan too tricky to give consistant results. Please explain what you mean by exactly 60 seconds in part B. I use a stainless reel in small Nikor tank, one roll at a time. Is it 60 seconds from starting to pour in to starting to pour out, or do you let it sit for 60 seconds and don't count the in/out times, or what? Thanks, Bill

-- Bill Mitchell (bmitch@home.com), October 05, 1999.

PMK stands for Pyro - Metol -Kodalk (Kodak's name for sodium metaborate). It is available in either a powder or liquid mix from Photographer's Formulary: http://www.photoformulary.com/index.htm. It has minimal effect on film speed. Grain is moderate to fine. It provides a beautiful tonal scale, especially in the highlights, which are almost impossible to block. The pyro stains the gelatin, so the negs looks greenish-yellow and need about a stop more exposure to print than ordinary negs. The developer is extremely easy and economical to use, with a very long shelf life. I use it exclusively, with Delta 100 & 400.


-- Peter Hughes (leonine@redshift.com), October 05, 1999.


I set my gralab for 1 minute and 15 seconds. When the second hand hits zero, I start the pour into a 16 oz tank tilted to allow the fastest pour. I agitate for 5 seconds when the hand hits 30 seconds. When the time hits zero and stops, I dump the "B" solution and immediately rinse with water, for about 15 seconds, then dump the water. Then I pour in rapid fix. I usually monitor the temperature of my darkroom and assume that the developer and fixer are at the same temperature. I get the rinse water close to that temperature.

I got tired of getting varying results with other developers. I used technidol for a while then standardized on Ethol TEC for the last 9 years or so. TEC is diluted 30:1 for tech pan and I used a syringe to accurately measure the small amount of stock. I always worried when pulling the reels for the first look as to whether the development would be right. About a year ago, some one on photo.net clued me on to Diafine and the 60 second "B" development time for tech pan. If you go to 1 1/2 minutes in "B", the contrast starts to build.

I've developed enough 35mm tech pan in Diafine at this point to have confidence in the results. I have zeroed in on an E.I of 80 that I use with my MF nikons.

-- Gene Crumpler (nikonguy@worldnet.att.net), October 05, 1999.

Gene, me again, still fence sitting, what's your web-page URL Sean yates

-- Sean yates (yatescats@yahoo.com), October 05, 1999.


It's http://home.att.net/~gene.crumpler. All of the work up now was souped with T-max, TEC, D-76, etc. I just converted to Diafine in the last 5 months.

-- Gene Crumpler (nikonguy@worldnet.att.net), October 06, 1999.

Moderation questions? read the FAQ