20x24" contact printing frame

[glbeas]

Right, theres a bleed valve and a vacuum gauge on most, my NuArc has it. You can set the vacuum from full to nothing with a twist of the valve.

[bobherbst]

A vacuum frame is a must for 20x24 for any semblance of image quality. Sandy and Nicholas explained it well. For those of you who think a clip or split back frame is OK try placing a 1/2" wide stouffer step wedge across the split or in the middle of a clip frame and expose it onto a piece of coated paper. I think you'll be sorely dissapointed. You'll see very clearly whether the frame is holding the negative and sensitized paper in contact. This is the test I have any student do who brings their own contact frame to a workshop. I've seen very expensive frames fail the test.

Does anyone know about who produces a 20x24" contactprinting frame ?