I had one made by Dan Pelland that is well made.
I had one made by Dan Pelland that is well made.
Keith Pitman
I use one made by Lotus Cameras -- very nice indeed.
I have a nice vacuum frame with motor that goes to 16x20 but I am contemplating doing some 20x30 or 30x40 monochrome gum prints ( one printing per sheet only, no registered emulsion layers) . Does any one know if paper sandwiched between two sheets of heavy thick glass would work for that? I'm probably not going to make or buy a giant vacuum frame.
Unfortunately John the larger the print the more imperative a vacuum frame becomes.
Ron McElroy
Memphis
I made a frame with a glass plate measuring approx 18x24"; the presume system consists of 4 crossbars (wood) with a total of 8 threaded rods through them, pressing down on the split back plate. The concept works and can be scaled up, adding more crossbars and pressure points as you go up in size. However, I feel that beyond the size of the one I made, it all gets quite impractical.
Frankly, anything loaded with simple springs at this size I wouldn't trust. Either the springs aren't strong enough to keep the contents pressed together well enough, or you need an unpractical number of springs, or the springs are strong enough to form a serious health risk (imagine one popping out uncontrolled - one could easily lose an eye).
There's probably a fair number of conceivable architectures that may work for larger frames apart from a vacuum system. But the spring loaded concept of the smaller frames doesn't look like a very good candidate to me.
Is ANR glass important in a printing frame? In my limited experience with contact printing I never had a problem with Newtons rings, but it is often a problem with glass negative carriers in enlargers.
Yes, unless you're contact printing sheets of 320TXP. It is the only film left I'm aware of that's still heavily back coated, ostensibly to enable retouching on both sides. I haven't heard of anyone doing that type negative retouching lately, but the coating sure does eliminate Newton's rings completely!
I never saw anything resembling newton rings in my alt process contact prints despite using regular glass. The possible exception is in photopolymer gravure where I used to have an issue with light spots, but that seems to have gone away as a result of other process changes. So no, I wouldn't say that for processes such as gum bichromate you need AN glass.
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