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Discussion in 'Ultra Large Format Cameras and Accessories' started by Falkenberg, Jul 9, 2008.
Does anyone know about who produces a 20x24" contactprinting frame ?
NuArc makes them that big and bigger. You may find them used from old print shops, I see one on Ebay every once in a while. I even have one about that size in my basement I got from work. You could even make one from the copyboard of an old process camera.
Photographer's Formulary has the greatest deals on contact printing frames. I have their 20x24 model. I could not have built it myself for what they charged me for it, especially once you consider labor time! 20x24 was only $100. Smaller sizes are less of deal, but still incredibly priced.
Their frames (at least my huge one) do not have the traditional long rotating springs on the back, but heavy duty clips around the perimeter. I suppose this could technically affect the contact of the film and the paper in the middle of the frame, but I have had no problems doing cyanotypes and contact prints so far.
Lotus View Camera (Austria). I have their 12"x10", expensive but extremly well made. The spring back is very strong indeed. See link:
Lotus makes the best ones and the shipping from Austria to Denmark will not be to bad.
Unfortunately for those in the US excahnge rates make Lotus frames prohibitively expensive. I am glad I bought mine almost 10 years ago.
PO Box 3433
Lake City, CA 96115
Doug makes very nice frames at a very reasonable price in my opinion. He deviates from the standard design a little bit, but I've been nothing but pleased with my 23X26 frame!
I have various frames, but for huge work, I just use a sheet of plywood (I don't know what they call it in Denmark) and a sheet of heavy glass (with no UV coating). For Arches Platine and most other papers the weight of the glass is sufficient. I have not had a problem for lack of spring steel pressure. This works both in my home-made UV light box as well as on my roof for free UV.
Second the vote for the Doug Kennedy frame. Mine works great, it's an 11x14.
Someone should do a side by side comparison of these frames. Anyone dare to compare the Lotus and the Doug Kennedy frames. Do any of You know if the 20x24" frames are exactly that size in the glass or if it is bigger. I use a 11x14" for 8x10" prints on 10x12" paper. I guess what I am asking is, if it is possible to fit a 22x26" (or 24x28") paper in these frames.
Normally speaking, the "size" of the printing frame indicates the maximum size sheet of photo paper it will take, and the largest film negative it will take. A 20x24 frame "should" take a piece of photo paper of 20x24" size. If you want to print on a sheet of 24x28" paper, then you need to have a custom frame made for that size.
The Formulary frames are inexpensive, but I wouldn't get one for 20x24". The back attaches with clamps that go around the perimeter of the frame, rather than leaf springs that apply pressure from the center of the back. I tried an 8x10" frame of this type at a workshop and didn't feel I was getting good enough pressure in the center of the frame.
Some contact printers say that for anything larger than 11x14" it's better to use a vacuum easel.
Bostick and Sullivan frames are very nice. Their frames are always somewhat bigger than the posted size. An 11x14 will be something like 12x15 if I'm not mistaken. Robert
my "20x24" frame was made the size I wanted to accommodate the paper size of my choice.
Doug Kennedy makes frames to order, so you can get exactly what you want!!!
Doug Kennedy replied to my mail and recommended his student frame. Do any of You have any experience with them ?
I have a monstrous 40x60" vacuum frame I'm planning to use, as soon as I manage to clear a large enough space to pull it out of storage.
For that size you need a vacuum frame.
A conventional design frame won't be able to put enough uniform pressure on the materials to assure really good contact. If the spring force holding the back on is 50lb then the pressure holding the materials together is only 1/10 of a lb per square inch. But the pressure won't be uniform because the glass will bow, so some places will have very little clamping force.
A 20x24 vacuum frame has a clamping force of 14 lbs per square inch and puts no force on the glass. The total force is 6,700 lbs and the pressure is uniform.
You shouldn't need to pay much for an old vacuum frame. They are a bit scarcer now than they were 10 years ago when all the print shops were throwing them in the dumpster.
Another thing to consider is a "plate maker".
As hobbyists are now the largest consumers of these products, the smaller units command premium prices on ebay & co..
The best solution for 20X24" and larger contact prints is a vacuum frame. However, if you are printing sillver with a point source or collimated light source it is possiblel to get good results with most contact printing frames, or even a thick sheet of glass laid over the negative and paper. I print AZO this way by simpy suspending a 5 watt night light some 40 inches from the frame.
However, if printing alternative processes with a diffuse light source such as bank of BL tubes it is almost impossible to get acceptable results with a contact printing frame in any size over 11X14. In this case a vacuum frame is essential ffor best work.
I print 24x30s and 30x40s with home made contact frames. I absolutely can't use a vaccum frame. It applies too much pressure. Too much pressure can push moisture from paper into the film, as you can imagine this is a problem.
This probably isn't a problem if you let your paper get bone dry, but my results are less than optimum with bone dry paper.
I would trust Doug's recommendation. I don't know if my large frame from him is or isn't a student model or not, but if is a great frame!
Well, my Formulary 20x24 frame works fine. Have used it for all sorts of things and it's sharp enough for me. At $99, what the hay.
Corey, Vacuum pressure can be adjusted I'm sure. Plus I have printed with pieces of transparent archival grade polyester film (from Light Imptressions) on both sides of the paper. This helps contain your paper's humidity and protect your negatives. The stuff works great. Robert
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.
Vacuum frame for 20x24
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.