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Selenium Toner (KRST) update
February 4, 2006
Some observations of the behaviour of Kodak Rapid Selenium Toner (KRST) over a long time including periods of use and periods of disuse. Recently I made some prints for the first time in too long. I've been keeping records on my present jug of selenium toner (KRST), which I first mixed in 2001. It's diluted 1+5 in distilled water. I normally keep around 3000 ml in the jug, but the level was quite low. I had not used it since early 2003, and apparently I did not top it up before I put it in storage. Examination of the contents of the jug of KRST showed it was quite clear, no trace of the characteristic murkiness that often darkens KRST. Also, a large amount of white fungus was living in it -- sort of like a miniature aurora borealis hanging in space within the solution. It seemed to hold together like a jelly fish. I poured it through a coffee filter, scrubbed out the jug, and filtered it through a fresh coffee filter back into the jug. It smelled fairly prominently of ammonia. I expect future regular and frequent filtering will keep the fungus from proliferating again. The first print I made was toned in the KRST before I added a liter of fresh mix to top it up. It toned as it had always done. I couldn't see any change in the action of the solution. The second print was made after I added 200 ml KRST concentrate plus 1000 ml distilled water to top up the jug. The toning action was as usual. The smell of ammonia was quite strong. So it seems to me a solution of KRST can last pretty much as long as one wants. As long as I'm active in the darkroom I don't see why I can't have this very jug or its descendents at work. Really, as a darkroom effluent, KRST need only dribble out in drainings from each sheet toned, not as a dumped container of solution. The solution now has toned the equivalent of 1098 8x10 sheets of FB material. I attribute the lack of precipitate in the used KRST to the absence of acid in my darkroom. regards, --le ________________________________ Lloyd Erlick Portraits, Toronto. voice: 416-686-0326 email: net: www.heylloyd.com ________________________________ -- |
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Selenium Toner (KRST) update
One would surmise diluted it would lose
strength more readily. OTOH I mixed KRST 1:9 yesterday from concentrate that must be at least 12-13 years old from a half full container (taken from the school lab I used to work at and stored in an old HC110 plastic bottle.) The strength seemed equal to the new KRST I bought last month. Kodak puts an expiration date on most of their packaged chems to cover their you know what. Either that or to get you to throw stuff out and buy new every couple of years. Lloyd Erlick wrote: February 4, 2006 Some observations of the behaviour of Kodak Rapid Selenium Toner (KRST) over a long time including periods of use and periods of disuse. Recently I made some prints for the first time in too long. I've been keeping records on my present jug of selenium toner (KRST), which I first mixed in 2001. It's diluted 1+5 in distilled water. I normally keep around 3000 ml in the jug, but the level was quite low. I had not used it since early 2003, and apparently I did not top it up before I put it in storage. Examination of the contents of the jug of KRST showed it was quite clear, no trace of the characteristic murkiness that often darkens KRST. Also, a large amount of white fungus was living in it -- sort of like a miniature aurora borealis hanging in space within the solution. It seemed to hold together like a jelly fish. I poured it through a coffee filter, scrubbed out the jug, and filtered it through a fresh coffee filter back into the jug. It smelled fairly prominently of ammonia. I expect future regular and frequent filtering will keep the fungus from proliferating again. The first print I made was toned in the KRST before I added a liter of fresh mix to top it up. It toned as it had always done. I couldn't see any change in the action of the solution. The second print was made after I added 200 ml KRST concentrate plus 1000 ml distilled water to top up the jug. The toning action was as usual. The smell of ammonia was quite strong. So it seems to me a solution of KRST can last pretty much as long as one wants. As long as I'm active in the darkroom I don't see why I can't have this very jug or its descendents at work. Really, as a darkroom effluent, KRST need only dribble out in drainings from each sheet toned, not as a dumped container of solution. The solution now has toned the equivalent of 1098 8x10 sheets of FB material. I attribute the lack of precipitate in the used KRST to the absence of acid in my darkroom. regards, --le ________________________________ Lloyd Erlick Portraits, Toronto. voice: 416-686-0326 email: net: www.heylloyd.com ________________________________ -- |
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