Vacuum frame question

[Brook]

I am canabalizing a vertical copy camera, part of which is a 16x20 vacuum system to hold sheet film upside down for exposure. I have the metal part with a million holes and the vacuum moter and a hose. Is it as simple as putting a paper/neg/ glass sandwich on it with the pump running and turning on the light? Anything more than this?

Thanks
Brook

 

[nze]

YOu may take a look to the plan available on the bostick and sullivan page I think you will find the answer to yur question.
http://www.bostick-sullivan.com/Technical_papers/Vacuum_frame_construction.htm

I will at least add some foam rubber.

hope this help
CHristian

 

[Donald Miller]

Unfortunately it is not as simple as what you suggested. When you use this for contact printing the first layer (the paper in this case) will be held in place with the vacuum being exerted. The film placed on top of the paper has no vacuum and consequently will not be held in place.

Typically the vacuum frames that are used for contact printing have a bladder that is drawn up against a glass which is installed above the paper/film sandwich. This then compresses the two together to affect a good contact.

Hope that this helps. Good luck

 

[Steve Roberts]

Ah yes! The million holes! I've just spent part of the weekend starting to make a vacuum printing frame for borderless prints. (All the ones I could find for sale were either too big, too pricey or both!) I've drilled 760 1/16th" holes in a 1/8th" thich aluminium 10" x 12" plate and now have to experiment with the vacuum arrangements. All good fun. Part of my plan is that I will also be able to use the thing for copying old photos, postcards, etc.. Before starting the marathon drilling session, I bought a pack of ten drill bits, thinking I'd probably break a few, but having gone to that trouble of course I didn't break a single one. Probably down to the quality of the drill bit rather than my drilling technique!
Best wishes,
Steve

 

[glbeas]

There is a way to use this without glass.You need to buy clear mylar in a sheet big enough to completely cover the vacuum board. Center the paper and neg on the board with the pump running and lay the mylar down, rolling from one side to the other so you can ensure the film stays on the paper. Using a soft cloth or a brayer roll any air bubbles out from the center of the sandwich. Give it time to pull it all down, you will be able to see it happen. Do your exposure and carefully put away the mylar. Best to keep it between two sheets of mount board as any kinks or scratches will show. This is also prone to static so use precautions to keep trash away and inspect carefully as you use it.

The vacuum board is really better for under the enlarger for borderless prints. You will need to lay scraps of paper or film over the unused holes to kill leaking air and get the maximum hold down during use.

This is a great find, are you going to try to make a ULF camera from the rest of the copy camera?

 

[Brook]

This is a great find, are you going to try to make a ULF camera from the rest of the copy camera?

Thanks for the info all!
It has been a great find. I am thinking of building a giant enlarger with the frame and bellows. I have another set of bellows I scavanged off a really huge copy camera and a portable ice fishing shack I an thinking of building a big camera obscura type outfit, using the vacuum easel/frame (which is it?) to hold the film. I think I can build a frame to mount a GG against to focus, remove the GG and place the film covered vacuum frameup to the frame.Should give perfect registration for the film/GG plane. Could be a cheap if not cumbersom way to get to ULF. And with an existing tent, maby wet collodian could be in my future....

Brook

 

[Bob Carnie]

Gary B , hit my answer right on the head before I could post, Oversized clear mylar is the answer, glass would not work well.