Thanks Ken, I keep the "Police" method in my list for further investigation ... :-) I've just a concern regarding the final wash and the back of the print, do you know if they turned the print to wash the back too ? Using a roller transport for such sizes is overkill as I will certainly not make lots of prints of that size. And my darkroom is in the basement with narrow stairs that require dismounting the machine. I had to build my sink inside the darkroom ... Thanks for these ideas, Claudio Bonavolta http://www.bonavolta.ch ----- Message d'origine ----- De: "K W Hart" <kwhart1@xxxxxxxxxxx> Date: Thu, 03 Jun 2010 08:22:43 -0400 Sujet: [pure-silver] Re: Methods to develop large size papers À: <pure-silver@xxxxxxxxxxxxx> I've never done this myself, nor even seen it being done, so I can only talk about what I've heard. I talked to a gentleman one time who worked in a police department photo lab. They routinely made large prints for use in court. They had a large sheet of masonite standing nearly vertical with a section of rain gutter at the bottom. The rain gutter had a pump attached with a hose. They also had a water supply hose and a floor drain. They would wet down the masonite so the paper would stick to it and lay the paper on it. then they filled the gutter with developer and used the pump and hose to spread developer over the paper. After the developer time had passed, they pumped the developer into it's storage container and used the water supply hose to rinse the paper, pumping the water into the floor drain. They filled the gutter with fixer and used the pump and hose to spread fixer over the paper. After fixing, the fixer was pumped into it's storage container, and the water hose was used to wash the paper. The paper was removed, the masonite washed down, and the paper was put back, clamped at the top, and left to dry.He told me this method worked well and they eventually switched over to processing color prints in this manner. I've been told that the method of 'seesawing' the print through a 'canal' tray works best with two people. Also a weighted roller (large diameter pipe?) should be used to keep the paper in the tray. You have probably used the seesaw method for developing roll film in a tray. Imagine that the film is no longer 2" wide, but 50" wide, and you'll see why you need to two people. For sponging the chemicals onto the paper, the paper should be tilted so that the chems run off. I considered at one time making a drum using large diameter PVC pipe and caps. This would require minimum chems as the pipe would be rolled to distribute the chems over the paper. I'm told that the problem is that the paper will adhere to the smooth inside of the pipe and be very difficult to remove. In your case, you would need a pipe over 16" in diameter. (circumference=diameter X 3.1417) With so many photolabs closing down, used roller transport processors are more available. You might be able to pick up a 50" wide model for a couple thousand. Of course you might also need a fork lift to to put in your darkroom, and 3 phase power to run it, so this might not be the most practical idea for one or two prints! Ken Hart----- Original Message -----From: Claudio BonavoltaTo: Pure-SilverSent: Thursday, June 03, 2010 7:21 AMSubject: [pure-silver] Methods to develop large size papersDear All, I'll probably have to develop large FB paper sizes (around 50"x75") soon, what methods would you advise ? I know the following methods: - roll forth and back the paper in a home-made "canal" deep tray. This one looks ok. - the sponge (let the paper on the floor on a large plastic sheet and apply the chemicals with a sponge). I know some that did it but don't see myself doing it ... - the home-made drum seems unpractical due to its weight Thaniks in advance, Claudio Bonavolta http://www.bonavolta.ch