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Darkroom Accessories: Print Washer

Don't want to build one? Got US$220? You can buy one from Versalab, or maybe you can get a deal on ebay Tools required
Materials required
Design
Calculations
Using your print washer
Comments

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Tools required

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Materials required

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Design

print washer The print washer is made up of Plexiglas, with wood holding it together. Individual 'paper compartments' are divided by Plexiglas within the outer box. There is a small area below the compartments where the water enters the box and then enters the individual compartments through holes in the 'false bottom'. This box sits on a base of 3/4" lumber (1 by). The wood around the top and bottom is there to hold the box together.
without wood This diagram shows the box without the wood attached. The box is 10 1/4" high, 6 1/2" wide, and 11 1/2" long. There are 6 dividers making 7 compartments of 9"x11"x3/4" each. You can build your washer to whatever dimensions you want though.
The sides, ends, bottom, and dividers are all cut from Plexiglas. I don't remember the size of the Plexiglas sheet(s) I purchased, it was 1986, but the dimensions of the pieces are as follows.
false bottom The false bottom has holes in it of 1/8" diameter to allow the water to flow from the bottom compartment into the individual paper compartments. The holes should be centered where the paper compartment will be. (I've drawn more columns in this drawing than there are in my washer, sorry). Put them about 1 to 1 1/2" inches apart.

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Calculations

  1. Determine the size you want your compartments to be. I found that if the compartments were not too deep, 3/4" was plenty to put my fingers into to get the paper, if I use this washer with 5x7 or smaller prints, I have to use a thin set of metal tongs to remove the prints.
  2. Determine the number of slots you want.
  3. Calculate the size of the box you want (allow 1" for the bottom compartment).
  4. Cut the Plexiglas sheet into the sizes for the pieces you need. (score one side of the Plexiglas with a sharp knife, run along a straightedge (preferably metal) then 'snap' the sheet in two. Be careful doing this, you need to make sure that you cut only once, and that it is a definite 'score'. If you cut twice, you are likely to make two 'scores' in it, and then when you snap it, it will break weird.
  5. Cut the holes in the false bottom. When you drill, start out slow, because Plexiglas is slippery, and you might slide all over the stuff if you aren't careful.
  6. stacking Stack the sheets using 1x4 spacers as shown. The dividers should be lined up with the top sides and slightly inside of the ends of the sides. (don't worry about getting the ends lined up, they will be adjusted as you connect the ends) The wood used in the stacking should not be glued to the Plexiglas, it is just used as spacers.
  7. Apply silicone caulk to the ends of the sides and dividers (the ends need a lot of caulk to prevent leaks, the dividers only need enough to keep them from moving about.
  8. Put more silicone on the ends where they come in contact with the sides, before attaching them.
  9. Connect the ends to the sides and dividers. Keep the tops of the dividers in line with the tops of the sides. Clamp the ends to the sides and dividers.
  10. Wait until the silicone is dry.
  11. Apply silicone to the inside of the box where the false bottom will sit, and on the bottoms of the dividers.
  12. Insert the false bottom, place the box top side down on something hard, and put weights on the false bottom so that it seals well.
  13. Wait until the silicone is dry.
  14. Apply silicone to the inside of the box at the bottom edge.
  15. Insert the bottom into the bottom of the box, and allow to dry.
  16. Cut the 1x2 wood into lengths that will allow an overlap of the thickness of the wood on all sides. (if the wood is 3/4" thick, and you are making your washer to my dimensions, you need to make pieces that are 8" for the ends, and 12 1/2" for the sides. You need 4 ends and 4 sides. Plus, you should make a row of them for underneath the box (I had 5 1x2x12 1/2" pieces for the base).
  17. Cut interlocking tenons in the ends of the wood. Allow a little extra length in the tenons so that there is room to tighten the clamp during glue up.
  18. Apply silicone to the outside of the box where the wood will be (that is the only way to glue wood to Plexiglas that I know of)
  19. Glue the tenons and clamp the wood in place. Be sure this is clamped tightly. Allow to dry.
  20. When the glue is dry, drill a hole in the center of the wood on either the end or the side, your choice, large enough for a snug fit of the female hose connector, and all the way through the Plexiglas into the lower compartment. Apply silicone and insert the connector into the wood.
  21. Drill a small hole (3/32" or 1/8") on the opposite side / end of the bottom compartment near the bottom. This is the drain, so it needs to be right at the bottom of the bottom compartment to get the water out when you are finished your session.
  22. When everything is really dry, test for leaks. If you have leaks, put additional silicone on the corners where the leaks are. If you can't get it to hold it's shape, wrap 12 gauge wire around the box in bands, and twist the ends to tighten, or build another row or two of wood holders.
  23. When there are no more leaks, silicone the base pieces to the bottom of the box.

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Using your print washer

finished washer Allow enough water flow to just barely come over the top of the washer, so it needs to flow a little faster than the water exits through the drain hole in the bottom. To 'archivally' wash prints, you need to test the washer before you can know the exact wash times. But I have found that with wash aid, and a pre-wash, I need 9 to 10 minutes within this washer for 'archival' quality. Your definition of archival is probably different to mine, so don't use my numbers!

Looking at my washer you can see lots of silicone on the corners, and wire wrapped around the outside. It's not real pretty, but it works.

Note: If you put more than one print into the washer, you need to wash all prints to the length of time required for the last one, since there will always be some dissipation of fixer from one compartment to another if you use one source of water, no matter what the design of the washer is.

Versalab Print Washer FAQ information applies to all print washers, including this one.

Have fun printing!

Nova Printwasher Information

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Comments

For drilling in the plexiglass, a simple trick is to use masking tape over the area to be drilled. No drill slipping at all.
--Duane Heller

Visitor Comments

The comments stated below are not necessarily the opinions of Andy Hughes or DarkroomSource

I have one suggestion for drilling the holes in the false bottom of the washer. You may be able to use a piece of pegboard (cut the same sizeas the plexiglas) as a template for drilling. this would keep the drill and bit from wandering and keep the holes in a straight pattern.
Contributed by   on 1999-02-06 00:00:00

I just read this in rec.photo.darkroom, I hope the writer doesn't mind my adding it here...

I'm in the process of building my own right now. We'll see how it works. Visit this site: http://darkroomsource.com/printwasher.htm for some design ideas. It is a good design, but I couldn't find a cheap source of plexiglass and I was concerned that cutting it accurately could be problematic. I also looked at the Versalab site for design ideas-- they also market one of the cheapest, most solid looking washers I've seen.

I went to K-mart and picked up two clear plastic storage containers, one large enough to hold the other. My current idea is to have water enter through a hose into a false bottom on the inner container, and have it spill over the top of the inner container into the larger container. A hose will drain the larger container into the sink. Prints will be held upright with PVC hosing, but there will not be separators between compartment.

Good luck, Christine
Contributed by   on 1999-08-09 00:00:00

This is another comment from rec.photo.darkroom, and I also hope the poster doesn't mind me including it here.

I made my own 20x24 washer with a garden seed tray and a length of plastic overflow pipe, only to discover my design had been already done by Kaiser. The seed tray was from a garden centre, made of tough polyprop and easy to work with.

Seal one end of the plastic plumbing pipe and drill a series of holes along it's length, in a pattern -_-_-_-, so the jets go at different angles. Drill a hole to accept the pipe about 1" from the corner, and glue along the length of one side, making the little holes (about 1/8th in diameter) aim across the dish. Drill a series of holes along the opposite side of the dish one row near the bottom, and another near the top. I make the holes at the bottom slightly smaller, since the increased water pressure favours the lower set. I then took the rubber tap end of a patterson force film washer and push onto the sticking out end of the pipe, cut off the hard plastic end of the hose and clamp to my tap. The entire assembly pops into my darkroom sink. The beauty of the design is that the water passes over both top and bottom of the print, so the print is not allowed to 'float' in the bath. I think the Kaiser ones stop at 12x16 size, but I am not sure.

If you need to wash multiple prints, then a Nova vertical system is excellent, takes up little space and can be used without a large darkroom sink handy. --regards chris.woodhouse@zetnet.co.uk

darkroom technical resources at www.users.zetnet.co.uk/ktphotonics
Contributed by   on 1999-08-10 00:00:00

Yet another posting from rec.photo.darkroom:

I built on for washing 16x20 prints out of plexiglass loosely based on the plans at www.darkroomsource.com. It cost US about $150 in materials, plexiglass is not cheap, but it works well. I tried to find a tub large enough for washing 16X20 but had no luck which is why I went this route. I also built the inner basket out of plexiglass with 10 slots for prints. I used a piece of PVC (har plastic) pipe across the top of one end, drilled holes in it so a small stream of water sprays in to each slot in the tray, drilled a hole in the bottom of the other end and put a small valve on it to regulate flow. The hose attaches to my shower.

It works very well but one thing I would do different is to cut out notches in the walls of the inner tray to make it easier to get smaller prints out. The other thing I would do is find a textured material for the walls in the inner tray so the prints don't stick to it.

If you can find a tub large enough you can make the inner basket for very little.

Good Luck.
Contributed by   on 1999-08-16 00:00:00

I had no idea it would cost this much. I guess the price of plexiglass has gone WAY up since I built mine. It almost makes sense to buy one now.

I do have plans for building a tray stack washer, which I'll publish soon.
Contributed by   on 1999-08-16 12:00:00

I'm building one using glass (It is a lot cheaper than plexiglass). You just have to sand down the edges so you don't cut yourself.
Contributed by   on 2002-04-19 00:00:00

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