Suggestions for building a print washergreenspun.com : LUSENET : B&W Photo - Printing & Finishing : One Thread
I have too much time on my hands, and am thinking about building a print washier. I have good access to large scraps of plexiglass, and am planning to build one where the prints are placed in the unit vertically. Specific questions I have:
Should the water enter from the top or bottom?
Should the water exit from the top or the bottom (does hypo sink or float to the top?)?
Should I install some type of syphon in the unit for water flow?
Should the unit have a false bottom that the prints rest on, with hole drilled in the bottom for water flow?
Should the water come into the unit at one point, or should there be a tube with hole so the water can "spray" in more evenly?
Any other general comments/information I need to know?
I know there is a plan for a print washer at darkroomsource.com, but wanted a few more ideas.
Thanks in advance for your suggestions and sharing your experience with me.
-- Jim Rock (firstname.lastname@example.org), November 10, 2001
Jim, I have given this subject a little thought as well, and built an 8x10 print washer out of plex for my little darkroom in Vienna (the main lab is in the US). From my experience I would recommend/like to have the following features on my washers (I'll try to address your questions in order):
"Should the water enter from the top or bottom?" My preference would be for top feed, having the water drain out the bottom into a chamber or chambers that would then fill and drain out the top as well. This allows the washer to stay filled when the water is turned off. Also, if you can use some kind of even feed from the top via a removable tray with lots of holes in it (I use a colander for my homemade washer) it may provide for a more even flow pattern, directly from top to bottom, eliminating any dead spots in the middle, which is a common problem with washers that have feeds in only one location.
"Should the water exit from the top or the bottom (does hypo sink or float to the top?)?" Covered above, but the question of hypo rising or sinking is really moot. The important thing is to get a good, even exchange of fresh water over the surfaces of the print. Washing is accomplished by ion exchange. It is, therefore, essential to have clean hypo-free water available to all surfaces of the print and have no dead spots.
"Should I install some type of syphon in the unit for water flow?" I think this is possibly a good idea but not essential. I would incorporate some kind of removable cap for draining the washer with the siphon.
"Should the unit have a false bottom that the prints rest on, with hole drilled in the bottom for water flow?" Yes! Preferably just a couple of strips to hold the prints off the bottom of the washer an inch or thereabouts. The water can then be siphoned from this area under the prints to the drain.
"Should the water come into the unit at one point, or should there be a tube with hole so the water can "spray" in more evenly?" Also covered in point 1 above. In my opinion, the more even the feed and drain, the better chance you have of eliminating dead spots.
"Any other general comments/information I need to know?" I would include provision to fill and, especially, drain the washer quickly. You would be surprised how long it can take to drain a 16x20 washer even with a 1" hose. I would want to be able to drain and fill the washer once or twice in the middle of the washing cycle as quickly and efficiently as possible (5 minutes or less). Replacing the water with fresh during the wash insures that any dead spots are replaced with fresh water. A large drain plug/hose would really help here.
Hope this helps a bit,
-- Doremus Scudder (ScudderLandreth@compuserve.com), November 10, 2001.
go to darkroomsource.com. there are specific plans and directions.
-- Ann C lancy (email@example.com), November 10, 2001.