I think the idea is saving water by recirculating
Is a pump really necessary? Won't water pressure alone do the job? I have never seen an archival washer that requires a pump.
I think the idea is saving water by recirculating
I think the idea is saving water by recirculating
I would think that by recirculating, the fixer would not be eliminated as well or as quickly.
I agree with Pieter. Recirculating keeps the fixer available to reenter the paper.
Nonsense, the fixer won't re-enter the paper. Once at equilibrium there's nothing to drive fixer in or out of the paper.
Two or three main variables.
Solubility of the fixer, optimum temperature is around 70°F, no point heating water and then running it down the drain, unless you are rich and don't care about wasting energy .
Recirculating the water allows for the fixer in the paper and the water to reach equilibrium (given time) 2 or 3 grams of fixer into 25,000 grams or more, water, and what 120 grams dry weight (?) of 10 8x10 sheets of dw paper.
The flow of water over the surface of the paper speeds diffusion of fixer from an area of high concentration to low.
Some of you folks are engineers, do the math. I don't like wasting resources.
So, as I understand it (and do correct me if I am wrong):
- Circulating the water (@20°C) during a certain time, and then draining, and to repeat this for an amount of cycles (how many?) would not only optimise the "equilibrium" AND save water, but at the end there would be no more a 'destructive' amount of fixer left in the paper? Ofcourse a Hypo Clearing Bath is applied.
- Would this approach the ILFORD way of washing FB paper?
PS1: actually this is somewhat what I am already doing for washing film: refreshing the water for 5 times and running each 'bath' during 2 min on a motorbase. When I then test the film with diluted Potassium Permanganate, it looks good.
PS2: by 'destructive', I would like to refer to what the Image Permanence Institute published (although, in all honesty, I don't fully understand their motivation due to a lack of scientific background).
The paper was still left on the dividers??? Wow, never heard of that one before. It can be miserable to remove when old. You can get a special solvent for its adhesive at plastic shops. Citrus solvent like De-Solv-It also works well if you're patient. Wear nitrile gloves; and if you need help from a putty knife, make sure it's a plastic one to prevent scratching the acrylic.
Thanks Drew. I will look into solvents when it warms up here. I imagine that the unit is well over 25 years old and was never put in use in the large lab it came from. I started trying to remove the paper off the panel dividers on the top of the unit and found it to be a very labour intensive effort. Thanks for the tip on using the plastic putty knives.
Well this is not a hot climate.When the protective paper gets 20 or so years old it can be a nightmare to remove, especially if stored in a hot climate.
This is the washer type I've used for nearly fifty years. Its biggest sin is that it misrepresents its capacity for the common size 12"X16" paper (alias 30cmX40cm). Only 12"x 15" actually fits.
So, as I understand it (and do correct me if I am wrong):
- Circulating the water (@20°C) during a certain time, and then draining, and to repeat this for an amount of cycles (how many?) would not only optimise the "equilibrium" AND save water, but at the end there would be no more a 'destructive' amount of fixer left in the paper? Ofcourse a Hypo Clearing Bath is applied.
- Would this approach the ILFORD way of washing FB paper?
PS1: actually this is somewhat what I am already doing for washing film: refreshing the water for 5 times and running each 'bath' during 2 min on a motorbase. When I then test the film with diluted Potassium Permanganate, it looks good.
PS2: by 'destructive', I would like to refer to what the Image Permanence Institute published (although, in all honesty, I don't fully understand their motivation due to a lack of scientific background).
This is the washer type I've used for nearly fifty years. Its biggest sin is that it misrepresents its capacity for the common size 12"X16" paper (alias 30cmX40cm). Only 12"x 15" actually fits.
My first unit had a clear acrylic tank which lasted about 10 years before cracking. My second unit now has the opaque tank and still works well.
My Paterson Major is plumbed to a darkroom tap through a clockwork Garden Tap Timer. I set the washing time and walk away knowing it will automatically turn off and wait to be emptied when I get back to it.
The most convenient feature is its capacity for 24 8x10 prints (two rows of 12) which is about a day's work for me.
I can buy one in Australia for about AUD $400 and I think that's very good value for the convenience it delivers.
You are killing your own argument. As you said, once at equilibrium, there is no more fixer taken from the paper. So, why recycle at this point? instead, fresh water needs to be aplied to kill the equilibrium and drive more fixer out of the print.
+1Nonsense, the fixer won't re-enter the paper. Once at equilibrium there's nothing to drive fixer in or out of the paper.
Two or three main variables.
Solubility of the fixer, optimum temperature is around 70°F, no point heating water and then running it down the drain, unless you are rich and don't care about wasting energy .
Recirculating the water allows for the fixer in the paper and the water to reach equilibrium (given time) 2 or 3 grams of fixer into 25,000 grams or more, water, and what 120 grams dry weight (?) of 10 8x10 sheets of dw paper.
The flow of water over the surface of the paper speeds diffusion of fixer from an area of high concentration to low.
Some of you folks are engineers, do the math. I don't like wasting resources.
@ Philippe-Georges: Just the method I'm using. First hypo-clear. A tray large enough for prints (diagonal size!) to swirl around, e.g. 55x55cm for 30x40cm (12x16"). Fill with ~<5cm (2") water ~<15litre, (4 gallons). Aquarium pump sends prints in merry-go-round; bumping into walls and jet from pump disrupt and shuffle the stack (1/2 dozen max). 10 min. Empty, refill, repeat. Empty, refill, repeat. My test with HT-2 shows washing OK at the end of second iteration. Third one is for peace of mind, and also because the color difference of HT-2 patches between "commercial" and "archival" is so slight.Sorry if my writing/formulating wasn't clear enough.
But I do refresh the water several times in succession according to a fixed rhythm (on a motorbase), when washing film, and with success (I think so).
And now I would like to practise this method for washing FB paper.
The only question is: what would be the best practice?
I would like to know this because I want to save water as it is too valuable too spoil (and too many people are in desperate need for it).
So I thought (hoped) to achieve this by washing in successive steps.
Each step: circulating the water with a (aquarium-) pump during a certain time, and then refreshing the water bath various times.
I just have to find out the duration and the rate...
+1
Restating what @mschem wrote (different people understand different wordings). The water flow has two functions: (1) promote the diffusion of hypo from paper to water, and (2) carry away the hypo. No need to renew water like mad if it currently much cleaner than the paper: won't improve the diffusion rate.
@ Philippe-Georges: Just the method I'm using. First hypo-clear. A tray large enough for prints (diagonal size!) to swirl around, e.g. 55x55cm for 30x40cm (12x16"). Fill with ~<5cm (2") water ~<15litre, (4 gallons). Aquarium pump sends prints in merry-go-round; bumping into walls and jet from pump disrupt and shuffle the stack (1/2 dozen max). 10 min. Empty, refill, repeat. Empty, refill, repeat. My test with HT-2 shows washing OK at the end of second iteration. Third one is for peace of mind, and also because the color difference of HT-2 patches between "commercial" and "archival" is so slight.
Do your own testing.
I am in the middle of building a 34inch x 44 inch x 14 inch stainless steel washer base on my Kostiner 20 x 24 washer.. Things that I am concerned about is the ability do drain equally each slot to the bottom I am not really concerned about huge water flow as many have pointed out that one really just needs the fibres of the. paper to leech out the fixer and it being heavier than water should fall to the bottom, the idea is to replace the complete washer many times and like many here hypo clear before going into the wash cycle, I believe I can do about 12 murals back to back with this method. There was a video of Clyde Butchers assistant using a vertical mural washer near their main sinks and I am going to go with that basic idea.
No. It implies a steady change of water, not repetitious tsunamis down the drain. Yes, the old Kodak tray siphon needs quite a bit more water continuously flowing through it than an efficient slot washer, but not a deluge either.
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