Recirculating print washer

[mshchem]

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.

 

[MattKing]

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.

 

[RalphLambrecht]

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.
View attachment 179822

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.

 

[mshchem]

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.

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 toilet , no water waste. I have some experiments to do here.
Another idea I have is before development pre wet the paper by soaking for 30 seconds in a tray of water, this would saturate the fiber base with water not chemicals that would need to be washed out.
Mike

 

[Neal]

Dear mshchem,

Nice idea. Re-piping so that the pump can empty the washer might speed things up. We look forward to your results.

Good luck,

Neal Wydra

 

[mshchem]

If I let my imagination get to me. I could envision filling the print washer with distilled water. Installing a mixed bed cation anion DI cartridge. Wetting the paper before development, doing a Ilford 1 minute fix rinsing the print for a few minutes. Let the DI cartridge remove everything, wash for an hour use no water.
Obviously there's no free lunch, what would be cost and capacity of cartridge, recharge of cartridge etc. ???
Maybe this should be left to MIT
Mike

 

[mshchem]

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.

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.
Water is plentiful where I live, it just drives me crazy to waste water.
ALL SUGGESTIONS WELCOME, Best Regards Mike

 

[Ai Print]

Thanks for posting this, I have been thinking of doing something similar. I'll watch the progress!

 

[Mike Bates]

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.

 

[mshchem]

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.

A gold standard test would be great. I worked as an analytical chemist for about 12 years, that was almost 30 years back.
All the apparatus I used is in a museum now. I need to do some research to see how the old Kodak Research folks did this sort of thing pre computer age. .
I have the reagents to make up residual hypo tests etc.
It would be great to be able to do a real assay for washing effectiveness. I need to go to a real library here at University of Iowa, see if I can dig up a colorimetric test etc.

 

[MattKing]

You might find it interesting to peruse the APUG sticky thread that Greg Davis initiated with respect to washing film: (there was a url link here which no longer exists)

 

[Jim Jones]

. . . I should be able to wash 12 prints in 15 gallons of water. . . .
ALL SUGGESTIONS WELCOME, Best Regards Mike

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.

 

[M Carter]

As far as testing goes, I have a book somewhere showing print washer testing, white prints were fixed the normal time and washed, each slot filled. Then they residual hypo tested each sheet, with drops in the corners and the center. They did find that some print washers didn't wash prints evenly.

if I were to test like this, I'd probably test the prints at several intervals as well. RST is pretty cheap considering you just use 1 drop per test. You could even make a testing neg with small boxes in the corners and center marked with time intervals to place each droplet on, and number the prints to correspond with washer slots, if you wanted to get super-serious about it.

 

[ic-racer]

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?

 

[John Koehrer]

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.

That was David Vestal, I think it was in Darkroom Techniques magazine.

 

[mshchem]

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 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.
Best Mike

 

[mshchem]

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?

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

 

[ic-racer]

How bad was the residual hypo test with conventional flow?

 

[MattKing]

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.

 

[mshchem]

Matt, I agree with you (mostly ) . The only phase of washing where the concentration of fix in the wash is very high (nearly equal to that of the paper ) is in the first 2 or 3, tray rinses. Then I put paper into a holding tray with water. Then 4 to 5 minutes in hypo clear., another quick rinse and into the washer. I think I will then run the recirculation pump for 20 minutes, the do a rapid dump and repeat the 20 minute cycle. There's not enough hypo in the wash water to inhibit hypo removal from emulsion or the paper base. This just takes time and gentle water flow over the paper . One problem I have always had is when I trickle water slowly, tiny air bubbles form on the emulsion. My pump will give gentle constantly flowing water. I haven't been able to do anything for the last couple weeks. I'm hoping to get in and do some tests soon. I don't think we are that far apart on our methods.
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.

 

[Ronald Moravec]

50 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

 

[mshchem]

50 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

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 wash .

 

[MattKing]

Like going to infinity, you never quite there.

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.

 

[mshchem]

Here's a picture of 1 gallon a minute

I'm sure there's water moving through the washer. However no real dramatic ripples, If you crank up the washer it gets very dramatic. I can't stand to see even 1 gallon a minute go down the drain for very long. When I use just the pump, I can see nice smooth gentle motion of the water, the pump creates the same nice current with the water running, from 1 GPM to a trickle. A fellow APUGer Marco B directed me to the famous "Mysteries of the Vortex" articles by Martin Reed. Reed states:QUOTE
"Degree of water exchange

Something I found surprising is that the traditional view that the presence of effluent hypo in the wash water can have a retarding effect is without substantial foundation, at least at the concentrations we’re dealing with here. Still water washing with sufficient agitation in a large enough fixed volume will still deliver a good thiosulphate level, and the presence of dilute fixer does not appear to have a significant effect on clearing time at either end of the washing sequence.


Agitation

The fundamental requirement is water movement at the surface of the print within a wash system, however this is generated. Water flow achieves this easily and effectively, although this can be looked on as wasteful of water when flow is arrived at from water inlet pressure. A small number of changes of adequate volume in a closed system that was well agitated mechanically or by re-circulation will give a good result."
END QUOTE

When I get around to making a couple hundred dozen or so 8x10 Dbl. wt. FB prints. I'm going to try a couple different scenarios. One thing that I am becoming increasingly keen to understand IS, do you need to run the water at all? Is a full (5 or 6 gallons) of water enough to take prints that have been fixed in rapid fix, hypo cleared, rinsed for a couple minutes in a tray, then run in a circulating pump driven washer enough to produce an acceptable print. If so how long to run and how many cycles?
I want to throw toning into the mess. And since (prepare to cringe) I want to try with a hardening fixer Kodak F-6, since (Cringe again) I like using belt dryers, have for 35 years w/o any problems, other than sticking to the belt, when not hardening the emulsion before drying. I am hoping to retire as soon as my wife will let me, I figure this will keep me occupied for the next few years.

I'm going to start with the Ilford rapid processing sequence technique, use non hardening Am. Thiosulfate since that's probably the most useful. I tone virtually everything in Se toner so I need to check that too. I have everything I need to do the Kodak residual hypo test, I wish I had an old school analog reflectance densitometer, one with a needle, no damn computers to measure the spots. I will check with some friends, I'm sure I can find something.
Anyway stay tuned, Mike

 

[mgb74]

That was David Vestal, I think it was in Darkroom Techniques magazine.

By chance, I'm looking at a "Pratt Institute Handout" by David Vestal; "Brought to you by Photo Techniques". Copyright 2002. In this he talks about fixing film and paper for 2 to 3x the time it takes to clear. He says the traditional rule is twice the time, but states that Kodak says some new films and paper require 3x.

In the article, he give a procedure to testing paper to determine time to clear (more difficult than film). In a nutshell, take a fully exposed (room light) piece of paper and:

1. run it through stop bath for 1 minute
2. fixer at 5 second increments (as you would do a test strip) for 5 through 5 seconds
3. wash for 2 minutes in running water with agitation
4. develop for 5 minutes
5. stop bath again for 30 seconds
6. rinse

All of this takes place in room light. You should have a range of black, grey, stained, and white sections. The first section that is pure white represents the minimum time to clear. He doesn't say that this is for RC or Fiber only.

There is also a description here.

Vestal attributes the method to a 1980 article, "More on Archival Processing", by George Holstead and Arnold Bailey.