I built my darkroom and sinks around the ability to print a maximum size of 30"X40" by tray processing. Paper is enlarged vertically to max by use of a 36"X48" drop table and wall mounted enlarging head. I gave up on processing large prints (> 20X24) by roll processing as the potential to crease and damage emulsion (fiber only) was simply to great for me. I print up to 30X40 from 40 and 42" rolls in large (32"X44") plastic Cesco trays, the same as with smaller sheet sizes. It's a bit tight with 42" roll paper, but still reduces handling only to moving from tray to tray. I use 5 of these large trays, committing one to wash by installing a homemade water distribution manifold and drain:
I shuffle up to six prints in the wash after toning and clearing baths (Permawash replacing water in the stop tray (TF-4 Fix)), while filling and dumping every 5 - 10 minutes as well.
This is how they come out:
18X30 (left), doorway, 30X40 (right)
24X40 & 30X40 on hanging walls (6'X8') in backroom
20X24 on far back walls
and
30X40 flanked by 20X24's
BTW, the warehouse personnel at Calumet LA, where I purchased the trays, laughed at me as I squeezed them into the back of my Toyota 4-Runner, quipping "Are you going swimming?"
I am currently working through the logistics of doing some prints larger than my current max of 16x20.
I have read through most of the posts in this forum on large printing. "The Negaive" has a chapter on mural printing also, and I have read it many times.
I'm thinking of a setup involving a single large tray that is at the level of my sink. It would be able to gravity drain and it would be filled manually with a bucket.
I want some system that I can take down when not in use. I thought I'd get one of those large "propagation trays" and reinforce the bottom with aluminum ("T", "L" or square) and fiberglass. Then I'd prop one end of the large tray on my bench by the sink and support the other end.
I found a number of possible supports at Northern Tool. Even a hydraulic table for $140 that could raise and lower the supported side to aid in emptying. Perhaps even something like this http://www.jcwhitney.com/jcwhitney/...8G&zmam=73771597&zmas=18&zmac=123&zmap=27878G
I found a 3" ball valve that seemed like it could empty the tray rapidly.
Thoughts, suggestions, etc..
bob,
IF you somehow did use a single tray method, You'd need
1. a HUGE drain, to empty the chems out of
2. a HUGE input valve, with a SUPER fast flow rate(primarily for LITH, snatch dev. and all)
3. a big cookie-type "cooling" rack. so that the print doesn't get sucked down into the drain. also, IF big enough, you wouldn't have to touch the paper at all. just the rack it's on. therefore, your "wet noodle" becomes somewhat rigid. and if it were made of stainless steel, you shouldn't get any contamination to the back of the prints.
something kind of like this, just MUCH BIGGER. lightweight(like 1-2lbs or so, just the rack) the rack in the pictures is like 5-6 oz.
-Dan
but bob,
if the screen is big enough, and the openings on the screen are say, 3/4" square, I don't think you should have any problems with "suction marks". but Flash G. would be the ideal operator though.
just an idea. you could also make a basket system, with something like this for the bottom:
http://www.mechanicalmetals.com/roundholeperforatedmetals.html.
so you essentially have a "flat" surface, to not create texture on the bottom of the print, due to the suction from the drain opening, but still would allow the chems to drain fast enough.
-Dan
-Dan
just putting some ideas out there.
A big version of a Nova slot-procesor would probably be the best way though, with Nitrogen burst, like a dip-n-dunk processor.
but for processing 50"x60", this would take up a bit of space though.
-Dan
just putting some ideas out there.
A big version of a Nova slot-procesor would probably be the best way though, with Nitrogen burst, like a dip-n-dunk processor.
but for processing 50"x60", this would take up a bit of space though.
-Dan
Working with large trays is very difficult even if you have lots of room, this is exactly why we wear Orange Jumpsuits here , the spilling of chems on one's body is almost a given.
I built my darkroom and sinks around the ability to print a maximum size of 30"X40" by tray processing.
This is how they come out:
18X30 (left), doorway, 30X40 (right)
24X40 & 30X40 on hanging walls (6'X8') in backroom
20X24 on far back walls
and
30X40 flanked by 20X24's
I print murals every week, and I cannot imagine using a single tray , in fact I think you would be opening the biggest can of whoopass trying to do it this way.
The lag time between dev and stop would be impossible to predict, flow lines and uneven development issues would be tremendous. I know there are those out there using single tray method for smaller prints , but for murals I see it as a very problematic way of working.
I would suggest a series of troughs that hold enough chemistry to completley immerse a rolled up mural and by rolling it through your hands and then rotating it back through the chems will work.
We run lambda murals this way in complete darkness.
For safelight work we use monster trays.
Single tray IMO would be nasty.
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