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Thread: print washers?

  1. #1

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    print washers?

    Im building a print washer. It'll be for 5-6 16x20
    Ive looked at various washers and each one works relatively differently
    some work by siphon action, some overflow and exit through an exit tube our outlet.

    Im trying to see if you definitely need the siphon action for the washer to work due to the specific gravity of the fixer? does it need to suction from the bottom where the fixer settles or can it just overflow from top and drip down?

  2. #2
    Tin Can's Avatar
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    Re: print washers?

    This will be interesting

    but first get your iPhone off the bottom...

    Quote Originally Posted by gmed View Post
    Im building a print washer. It'll be for 5-6 16x20
    Ive looked at various washers and each one works relatively differently
    some work by siphon action, some overflow and exit through an exit tube our outlet.

    Im trying to see if you definitely need the siphon action for the washer to work due to the specific gravity of the fixer? does it need to iPhone from the bottom where the fixer settles or can it just overflow from top and drip down?
    Tin Can

  3. #3

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    Re: print washers?

    ha! thanks for catching that, ive only got one broken iPhone.

  4. #4

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    Re: print washers?

    The notion that fixer is heavier than water and settles to the bottom of the washer is a myth, propagated largely by Fred Picker to sell his print washers. Think about it; the fixer doesn't settle to the bottom of the fixer tray during a printing session does it? Nope, it stays stable as a solution the whole time.

    Print washing, after the fixer is rinsed from the surface, proceeds by diffusion, which means that the fastest wash will happen when the paper is in contact with fresh water. If the fixer builds up in the wash water, it will slow the wash, which means that working on even and thorough (but not necessarily rapid) exchange of water is key.

    So, when you design, keep in mind that the important thing is to have good water exchange over the entire volume; no dead spots in the corners or along one side. This means having multiple places for the water to exit as well as an even feed.

    A small-volume washer might benefit from a siphon action fill-and-dump routine, ideally, one that could be manually activated at, say, two or three times a wash at the operator's discretion. A large-volume washer would waste too much water and take to long to fill.

    If it were me, I'd design a washer with a drip-type feed that covered the entire top surface (e.g., a grid of tubing with holes, etc.) and a number of exits that draw water from the bottom of the washer and then up the sides and exiting at a point that would keep the washer full and the prints submerged when the water was shut off. The slots for the prints can be simple separators like nylon line or whatever. Prints may simply stick to large sheets of plex used as dividers, thereby preventing water from reaching one surface. Water needs to flow along both sides of the print. I'd also provide for a siphon drain somehow (I often dump my big washers halfway through the wash by simply using a length of tubing as a siphon).

    A test for thorough water exchange is to add potassium permanganate to the water and see how long it takes to clear and if it persists in certain areas. Kodak's recommendation is a complete change of water every five minutes.

    Whatever design you decide on, be ready to modify it as needed. You'll need to test some prints for washing efficiency with HT-2 as well as do water-exchange tests. I'd simply fix several sheets and then drop them in your washer. Yes, you'll have to use full-size sheets for this, but the peace of mind will be worth it later. Then, at regular intervals after about 30 minutes, you should pull a print from the washer and immerse it in a tray of HT-2 solution to check both the rate of washing and to see if the washing action is even. It could be that some areas of the print are fully washed, but others not.

    If you identify an area of the washer that is not doing its job as well as other areas, then modifications would be in order.

    Hope all this helps,

    Doremus

  5. #5

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    Re: print washers?

    Doremus,

    Might try a vertical washer and leave the prints in for awhile and then do some testing to see what reality is on this one. The results may surprise you.
    ” Never attribute to inspiration that which can be adequately explained by delusion”.

  6. #6

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    Re: print washers?

    Thank you so much. this is the best tip ive seen by far. I appreciate it. that is what I thought about the fixer. I plan to use FT-4, which I believe is easily washed and diluted.

  7. #7

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    Re: print washers?

    My first and still my most efficient washer, I built of plywood from plans in Petersen's Photographic magazine. It was a fill and dump syphon. Where most syphon washers only dump a small amount, that one dumped all but about 2 inches of water in the bottom.. I made it for 11x14 prints, and it was 12 inches deep. Whenit dumped,it was obvious. % dumps were sufficient for a very effective clearing of salts. I wish I still had it,or at least the plans, but no luck there,.

  8. #8
    ic-racer's Avatar
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    Re: print washers?

    Fixer at the bottom... if you dilute your concentrated stock solution with water like this...
    https://mixthatdrink.com/how-to-pour...ered-cocktail/

  9. #9

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    Re: print washers?

    I'd follow Zone VI's basic design anyhow. The 16x20 print washer is 27" long by 20" high by 11" wide. Its an out of sink washer with an overflow. Yours would not have to be that wide, space between Zone VI dividers is 1/2" O.C.. Here are some shots of the basic 8x10 washer:

    Click image for larger version. 

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ID:	205939 16x20 washer showing the horizontal stiffener Click image for larger version. 

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    The clear sides of the 16x20 are 1/2" plexi, the black ends are double 1/4" plexi. There is a 1/2"x 1.5" horizontal plexi stiffener that runs the full 27" length, 5" down from the top. If you made yours 23" clear horiz space with 1" at each end for the fill and dump areas, so say 26" long with an extra 1/2" at each end. If you only need 6 spacers, and you made them 1" O.C., that's 8" plus 1" for the sides, so say 9" in width. The Zone VI one holds more prints. Any specific questions, PM me. Good Luck!

  10. #10
    Olli Jaakkola
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    Re: print washers?

    During my years in science lab I have made hundreds of density gradients by pipetting salt solutions of decreasing concentrations (KBr) on top of each other in centrifuge tubes. It had to be done very carefully not to mix them totally. Any flow or movement would destoy the formation of the gradient. It's practically impossible to get any spontaneous gradient formation even in undisturbated salt solutions, not to mention the effect of any flow or mixing. In print washing the concentration difference of thiosulphate in the print and the surrounding water determines the rate of diffusion and water replacement keeps it going.

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