I have used film holders in 2000 mil tanks with great success. I have settled on a simpler idea. Take one film holder, and bend the handle 90 degrees creating a "L" shaped holder. Place the film emulsion up in the holder and use a 8X10 or 4X5 tray. The holder does a excellent job with PMK, and you can keep your fingers out of the chemical. I beleive that having the emulsion faced up prevents abrasion from the tray bottom, and results in better PMK flow over the emulsion.(posted 8630 days ago)