Old Dektol
I just set up a temporary darkroom.
Boy, ho, boy ,oh boy is the Thomas sodium safelight nice to work with. As is the forty year old Beseler 23C. I found some dektol stock that I had mixed over four years ago with the intention of developing some prints and stored in a mylar wine bag. It had just a bit of discoloration so I mixed it 1:1 and tried it out. I got black blacks and white whites, no "muddy" prints and the image came out in about fifteen to twenty seconds. Three hours and twenty prints in the tray and it was starting to discolour (turn a bit brownish) One of the reasons I stopped darkroom activity was the resin coated paper that came out. It seemed to give slick and plastic looking prints. The AGFA resin paper I used today gave very nice prints. I'm going to mix up a new batch of dektol and see how much nicer the prints do get. The Tmax 400 I develped in 1:1 D76 gave a really nice negative to work with. I did over develop the film by about 5% It is a good start. It seems there have been some very nice advances in the B&W field since the 70's I hope there will be more spare time in the near future so I can play more. My 20 year old son is really impressed with the 7 x 10 glossies, I will have to wait a few days to see if I like any of them... |
Old Dektol
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Old Dektol
On Sun, 22 Feb 2004 01:10:48 GMT, "Richard Knoppow"
wrote: Pretty amazing. I've never stored a filled bottle of Dektol for very long. A partially filled bottle may last for six months but will start to get quite brown after that. Dektol is slightly straw colored when freshly mixed. Kodak's figures on lifetime of chemicals is quite conservative. They give worst case numbers to insure the products will work satisfactorilly. BTW, really badly oxidized Dektol will be black and smell like spoiled fish due to the hydroquinone. This stuff came out of the mylar bag straw coloured. I wanted to see if it would still work before I mixed a new batch. I did about 30 8x10 prints on one tray of dektol mixed 1:1 The last two prints came out "muddy", there was also a brown perciptate on the bottom of the tray at the end of the session. I do suspect this stuff was dying in the tray. |
Old Dektol
wrote in message . ..
On Sun, 22 Feb 2004 01:10:48 GMT, "Richard Knoppow" wrote: Pretty amazing. I've never stored a filled bottle of Dektol for very long. A partially filled bottle may last for six months but will start to get quite brown after that. Dektol is slightly straw colored when freshly mixed. Kodak's figures on lifetime of chemicals is quite conservative. They give worst case numbers to insure the products will work satisfactorilly. BTW, really badly oxidized Dektol will be black and smell like spoiled fish due to the hydroquinone. This stuff came out of the mylar bag straw coloured. I wanted to see if it would still work before I mixed a new batch. I did about 30 8x10 prints on one tray of dektol mixed 1:1 The last two prints came out "muddy", there was also a brown perciptate on the bottom of the tray at the end of the session. I do suspect this stuff was dying in the tray. The mixed developer is slightly yellow as mentioned above but the powder should be pure white. Any indication of a yellow or brown color is a sign the developing agents have begun to oxidize. Since this shows that the bag is leaking other components which can be oxidized will also be. This is mostly the Sodium Sulfite. Sulfite performs several functions in developers but one of them is to protect the developing agents by preferentially absorbing oxygen. The sulfite is oxidized to sulfate. Sulfate is white but doesn't absorb oxygen since its already oxidized. Metol and Hyroquinone both generate a yellow dye as they oxidize. When badly oxidized Dektol looks like coffee grounds and smells awful, probably from the Hydroquinone. I've opened a couple of bags of Dektol that looked like this. Bought very cheap at a camera sale, they were no bargain. I tried mixing one out of curiousity. The resulting liquid was also nearly black. I tried a bit of fogged paper in it, it simply stained the paper. Old devloper in sealed cans is probably OK. These cans were hermitically sealed. The bags are made of a layered combination of paper and metalized plastic. For some reason they tend to become leaky and don't usually have a very long shelf life. Kodak has recently changed its packaging to a metalized plastic which is seamed on only one side and should be more reliable. IMHO nothing will ever match the old tin cans.:-) Richard Knoppow Los Angeles, CA, USA |
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