what a great setup.You could you run it for a few minutes without adding fresh water,then dump and refill? Doing that a few times would make for very effective washing.Phase one. Pump to circulate water. Next step set up a dump and refill setup. Idea is to run 3 , 5 gallon washes rather than 1 gallon a minute for 45 minutes, Thoughts? Dump water goes to pre rinse prints before putting in washer. Mag drive pump from a Noritsu processor. Kinda thinking a gas burst agitation might be cool too.
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The old Kodak books by CEK Mees state that with each change of water you remove something like 90% of the hypo. A toilet tank in a public rest room would be a perfect print washer , every 10 minutes or so someone would flush the toiletwhat a great setup.You could you run it for a few minutes without adding fresh water,then dump and refill? Doing that a few times would make for very effective washing.
Washer holds a little bit over 5 gallons. I usually wash prints in trays. I think archival print washers leave a lot to be desired. If you turn the flow down, air bells form on the paper. I'm trying to figure out a way to agitate the water, and rapidly dump and fill the washer. I think I can use a large hose on the drain and syphon off the contents in less than 2 minutes. Then I will either dump in a pail of water or fill with hose. I should be able to wash 12 prints in 15 gallons of water.A gallon a minute seems extremely high. Kodak's recommendation for water flow and fibre based prints is to have water flowing rapidly enough to replace the water in a tank or tray once every five minutes.
A gold standard test would be great. I worked as an analytical chemist for about 12 years, that was almost 30 years back.It looks it should be very effective, but I wonder how to test it compared to other wash strategies. I vaguely recall reading about someone performing residual hypo analysis on prints after differing wash intervals. I think he left one print in the washer overnight in standing water and it turned out to be the best case. I might not be recalling that correctly.
I'd be curious if there is a test to show three five-gallon washes with self contained circulation, each 15 minutes, is as good or better than a 45-minute continuous wash at a 1/3 gallon per minute flow rate. They will use the same amount of water and the prints will be washed for the same amount of time.
When doing high volume printing in college, I estimate using about two ounces of water for each sheet of 8x10 RC paper. Fiber paper should have needed more water. Very few of my hundreds of left-over prints show deterioration even yet, almost 50 years later. Three deep dishpan trays were used with constant shuffling about 30 prints per load. After each load, the first tray was discarded, the second tray dumped into the first, and the third tray into the second. The third tray was filled with fresh water. It helped to have a companionable friend to do the washing and drying during those long otherwise tedious hours, and it augmented her limited finances. Sometimes ancient techniques beat modern gadgets.. . . I should be able to wash 12 prints in 15 gallons of water. . . .
ALL SUGGESTIONS WELCOME, Best Regards Mike
It looks it should be very effective, but I wonder how to test it compared to other wash strategies. I vaguely recall reading about someone performing residual hypo analysis on prints after differing wash intervals. I think he left one print in the washer overnight in standing water and it turned out to be the best case. I might not be recalling that correctly.
I'd be curious if there is a test to show three five-gallon washes with self contained circulation, each 15 minutes, is as good or better than a 45-minute continuous wash at a 1/3 gallon per minute flow rate. They will use the same amount of water and the prints will be washed for the same amount of time.
I never use a washer for RC paper. This is just for fiber base. I agree with (most) of what your getting at here. I've never had a print go bad over 50 years either, and I rarely use these washers because they take so darn much water.When doing high volume printing in college, I estimate using about two ounces of water for each sheet of 8x10 RC paper. Fiber paper should have needed more water. Very few of my hundreds of left-over prints show deterioration even yet, almost 50 years later. Three deep dishpan trays were used with constant shuffling about 30 prints per load. After each load, the first tray was discarded, the second tray dumped into the first, and the third tray into the second. The third tray was filled with fresh water. It helped to have a companionable friend to do the washing and drying during those long otherwise tedious hours, and it augmented her limited finances. Sometimes ancient techniques beat modern gadgets.
It would not be nearly as effective. Its serial dilution. Think about you have a ketchup bottle you want to rinse out. Put 100 mL of hot water in the bottle shake the P**s out of it dump it. Repeat 3 times, or drizzle a stream of water in, even with a tube inserted in the bottle. Same principal.If you fill it four times in an hour for, say a total of 20 gallons, why not run it with continuous fresh water at 20 gallons an hour?
The problem with this analysis is that it assumes that the wash "rinses" out the hypo. Unfortunately, that is not how the process works. Instead, the thiosulfate leaches gradually out of the paper and the rate that it leaves the paper is a function of both the mechanism of leaching and the difference between the concentration of thiosulfate in the paper and the concentration of thiosulfate in the adjacent water.It would not be nearly as effective. Its serial dilution. Think about you have a ketchup bottle you want to rinse out. Put 100 mL of hot water in the bottle shake the P**s out of it dump it. Repeat 3 times, or drizzle a stream of water in, even with a tube inserted in the bottle. Same principal.
The water leaving the washer should IDEALLY have the same concentration of thiosulfate (or higher) as the paper does, or you are wasting water.
Best Mike
The problem with this analysis is that it assumes that the wash "rinses" out the hypo. Unfortunately, that is not how the process works. Instead, the thiosulfate leaches gradually out of the paper and the rate that it leaves the paper is a function of both the mechanism of leaching and the difference between the concentration of thiosulfate in the paper and the concentration of thiosulfate in the adjacent water.
Washing is most efficient when there is a slow, steady replacement of thiosulfate laden water adjacent to the paper with fresh, thiosulfate free water.
If you replace the water too slowly, it will become saturated with thiosulfate near the paper and too much will remain in the paper.
If you replace the water too quickly, the thiosulfate doesn't have time to leach out of the paper at anything near an optimum rate. Your washing will be complete in the same amount of time, but will use more than the necessary amount of water.
This is what I have done. I'm trying to figure out how to use these washers I've accumulated over the years. I buy things used, as I can't resist a bargain. I rarely use these things because they seem so wasteful. I'm betting that time and circulation is more important than a lot of fresh water turnover in these big washers. Maybe the best solution would be, after HCA, rinse briefly in a tray, run in the print washer with just circulating water, no running water, then a final rinse in a tray for 5 minutes. The best setup would be to have 4 or 5 washers setup in cascade, but I'm not a commercial printer. My guess, not a recommendation, is you could safely drink the water coming off these washers. If I had to use these commercially I would put in a cistern, and use the water for laundry, toilets etc. Maybe open a car wash50 years of washing in trays with never a bad print. Agitate by interleave in one tray while a second refills. Use 8 trays of fresh water. Kodak rep was impressed and they had reps in 1980.
Running water will work at big waste of water because you really never get clean water, just diluted dirty water. Like going to infinity, you never quite there.
Fill and dump in a big washer takes too long and I believe it needs agitation. Burst might be good so test. Rescuing relatively clean wash water seems good for some quick rinses before comencing archival wash.
My method works as it satisfies all requirements at cost of hand labor
The up side of this is that it is actually beneficial to leave trace amounts of thiosulfate in the prints. By "trace", I mean very small amounts. So it is good that you never get there.Like going to infinity, you never quite there.
That was David Vestal, I think it was in Darkroom Techniques magazine.
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