Reverse Rolling/Flattening From Long Roll Cuts?

[John Layton]

Having just completed construction of a horizontal enlarger - one of my remaining issues for "going large" (42X60) is that of reversing the curl of sheets cut from a 42" wide x 98' long roll of Ilford MG Classic paper...so that it will remain reasonably flat for upcoming printing/processing steps.

I know that others have had success in utilizing an existing curl to advantage for processing...but the system I'm designing needs to have the paper reasonably flat.

I've been using a home made jig to cut paper for 20X30's (from a 42"X98'roll) - which can easily be used to go larger. My question is: if I cut a 42X60 sheet, then "reverse roll" this onto a roughly 3" diameter tube - how long should I leave this sheet in this (reverse rolled) configuration to produce a sheet which will remain reasonably flat for the printing/processing duration?

[xkaes]

Congrats on your new enlarger.

This topic was recently discussed -- undoubtedly to death -- so if you do a search, it is likely to show up. I use rolls up to 54" in a horizontal easel. I have a home-made 8x5 foot easel hanging from hooks on the ceiling. The edges of the easel hold the paper in place, but only for very large pieces. But for ALL pieces, I tack it to the easel with lots of masking tape -- starting on the top edge. This is, of course, easier with B&W since I can use a safelight. With time, you can get it done with color, as well. Having an assistant is not a bad idea either.

I have never reverse rolled any paper before exposing it. The heavy weight of the paper, gravity, and masking tape do a good job of keeping the paper flat. PLUS, due to the distance between the negative and the paper (ex. 15 feet), depth of field is much greater, compared to small prints. Whether or not you decide to "reverse roll" etc., I'd start by using a "small" sheet and then start working up to larger pieces. You may discover that there is no problem that needs resolving.

[John Layton]

Thanks! While I'll probably be OK not reverse-rolling prior to printing....my concern relates to the fact that for processing I'll be building and using a single large tray - on a "tilt-able" base - with a tapered end with an attached (closeable) drain. I'll pour chemistry over the print and either rock it or simply leave it tilted with the drain open to pour into one of two open containers - the other being used to re-distribute solutions over the print. If the print is not reasonably flat going in (dry) - then I may have some difficulty getting solutions to sides/edges of print in a timely manner.

But I suppose I could mitigate these concerns by giving the print a good pre-soak to help ensure flatness for the remaining steps. I'll just have to set up and give it a try!

[xkaes]

You can go down the tray route, but you will be sorry. You could possibly find six foot trays at a hefty price -- or make them yourself -- but they are basically impossible to use. Unless you work in an auditorium, it's impossible. And getting the chemicals in and out is also a waste of time. And how do you regulate temperature?

The way to go is with troughs. Think of the snowboarders half-pipe -- with each end closed of. I use 12" diameter PVC pipe -- cut lengthwise and glued shut on each end. FOUR five foot troughs takes up less space than ONE 5x8 foot tray. PLUS troughs use a gallon or less of chemicals -- that's 1/10th what a tray would use!

With troughs, the curl of the paper is a plus. It makes them easy to slip in and slip out. Think of the snowboarders again -- they fall back INTO the pipe. With trays you will produce nothing but GIANT creases. If you think mural paper is heavy dry, try to handle it when it is soaked!!! THAT's when you want it rolled up, and that's what a trough does.

A company called MAXELL made some mural tube processors years ago, but you will never find them. The troughs are better anyway, because you can see how processing is progressing -- at least in B&W. Still, it's best to run a small sample through before you waste a BIG sheet of paper.

[bob carnie]

John

use a metal sheet for your easel paint it black, and find long magnete strips .. no need to reverse curl..

Also when doing large murals I would use under the bed plastic troughs, and scroll the paper as per above. three large units... and one big tray for washing.. You will use a lot of chem doing murals any way you go.

one single tray would be horrific unless you have a really well thought out system for putting chem in and getting out fast.. the flow marks would be impossible .

I have heard of people using tilted trays and spraying on the chems with a continuous reclamation ability but once again need to really work this system out.

I have been making murals for many years and the troughs are really good for Lamda rolls , I do 30 inch x 10 ft at a time with no issue.

also I do have enough room for trays so I can do it the easiest way which is tray to tray.. making some 20 inch x 48 ortho film today and did 6 units in a few years without a sweat.

[bob carnie]

John this is a 48 inch sheet of film I am holding up.. my trays are exactly that. as you can see a simple set up , hard plastic trays with a large wash tray to my left...this image was taken 5 min ago.

[xkaes]

You will use a lot of chem doing murals any way you go.

With my 12"x5' troughs, I use one gallon of each chemical -- B&W or color. That's not that much more than a 20x24" tray. And with smaller troughs, say 8"x3', you could use a lot less.

I use a scooper to get the used chemicals out -- no big deal with only one gallon.

[bob carnie]

Thanks! While I'll probably be OK not reverse-rolling prior to printing....my concern relates to the fact that for processing I'll be building and using a single large tray - on a "tilt-able" base - with a tapered end with an attached (closeable) drain. I'll pour chemistry over the print and either rock it or simply leave it tilted with the drain open to pour into one of two open containers - the other being used to re-distribute solutions over the print. If the print is not reasonably flat going in (dry) - then I may have some difficulty getting solutions to sides/edges of print in a timely manner.

But I suppose I could mitigate these concerns by giving the print a good pre-soak to help ensure flatness for the remaining steps. I'll just have to set up and give it a try!

Pre soak would do the trick as the paper then would be flat and you could lay in place.. presoak in Safelight dude.

[xkaes]

John this is a 48 inch sheet of film I am holding up..

Just curious, are you really nine feet tall?

You can save a lot of space, chemicals, etc. with troughs, but to each his own.

[bob carnie]

With my 12"x5' troughs, I use one gallon of each chemical -- B&W or color. That's not that much more than a 20x24" tray. And with smaller troughs, say 8"x3', you could use a lot less.

I use a scooper to get the used chemicals out -- no big deal with only one gallon.

How big are your prints.. I had a friend who used a jobo system for ciba prints with absolutely no issues... Many ways to skin the cat, I have settled on large troughs and large trays for my work.