What is a Vacuum Board ?

I posted a question last night requesting advice related to contact

print frames. Someone suggested I use "vacuum board". I have

Goggled this to death, but still don't know what it is. Anyone ?

 

Thanks

Paul

 

 

wideawakephoto.com

On the back of Process Cameras you find an opening door which, on the inside, has a surface covered with holes. The camera operator places the film over this surface and hits a switch which turns on a vacuum that pulls thru these holes, locking the film in place. The door is then shut and the exposure made.

The reverse is true too; where an enlarger or process camera projects back on a wall; where the print to be exposed is held in place by the "Vacuum frame" A vacuum board can be sort of a slang phrase for a mounting press; to mount photos on foam core; where the glass pulls the image on the foam; and makes most wrinkles magically vannish

Our mounting press is also a contact frame; there are two lights on a track above; one can expose a 35x44 contact print.

I think that was me. I was referring to a board with holes, hooked up to a vacuum. Mine

looks like a slightly thick enlarger base board, with lots of tiny holes, and a connector for a

vacuum hose. I use a small, ordinary shop vac, 1 hp. This is just like contact printing with

a sheet of glass, except the glass is pulled down tighter. Some of these boards were made

for borderless printing on paper, no easel needed.

The "vacuum board" that was referred to, in the context of the original message, is a contact printing frame that maintains perfect contact between paper and negative by means of a system consisting of a vacuum motor and a hose running from the motor to the printing frame. The frame has holes in the base over which the paper and negative are placed and the vacuum motor creates a suction effect that maintains the perfect contact between negative and print that's needed when contact printing.

 

For contact prints in the 8x10 range a vacuum system isn't needed, the clamps found on the back of all good contact printing frames should be sufficient to mainttain the necessary contact between paper and negative. But as the prints get larger that becomes more difficult to do with by using clamps alone. Vacuum frames are designed to deal with that problem.

 

The vacuum motors are usually noisy so if they're going to be used a lot they're often kept in a room separate from the darkroom where the frame is located, which means a long hose then has to be run from the motor to the frame, which means they often aren't practical in a home environment.

At our shop we use the "NuArc Vacuum Frame"; for at least 3 decades. I guess the "Vacuum Board" is a Photo.net term.:) It is used for contact printing up to 35x45 inches; and also mounting prints on foam core. I have two different lamps on a track; that are moved into place above the frame; when doing contact printing. The hinged glass "FRAME" is horizontal when closed; the glass holds the negative and paper in good contact. a vacuum is pulled; the GAF timer is set; you expose the contact print. Then the vacuum motor is turned off; the handles of the Vacuum frame; are opened; the air rushes in. Then the exposed print is carried under safelight to be developed in the huge tanks. <BR><BR>Our other Vacuum Platen/ (board) is in house designed; 4x8 feet in size; and holds prints by vacuum; when enlarging. The board is vertical; with 4465 holes; on a 1x1 inch grid; all drilled by 1/4 hand drill; and countersunk.. <BR><BR>The bigger process camera uses a "Vacuum back" to hold film up to 24x36 by vacuum; the same deal; with a mess of holes. The "copy board" of the process camera uses a glass plate; about 6x12 feet; with a piece of mylar that covers the back of the orginal; paper of film to be exposed. A vacuum source pulls the mylar sheet against the glass. The mylar sheet moves up and down the "copy board" back on a track; sort of like a rolled up giant window shade. <BR><BR><b>These terms are mixed because Graphics Arts; Repro; Process camera; Lith and Printing are abit stepchilds of the "Large Format Cummunity". Graphics arts had its own photo catalogs; papers; dealers; favorite lenses; chemicals; salesmens; but is really mostly ancient history. The terms are different; because the industry was different.</b><BR><BR>In Graphics Arts we had Kodak Super-K projection paper in the 1960's; that required little washing. This was before RC papers came out for still photographers. Alot of special photo Mylars in 42 inch rolls; Kodagraph Developers; UV sensitive autopostive papers; P1 an P4 projection papers were the norm. A mess of lith negatives too. The scrapping of all these cameras is the reason so many process lenses have surfaced on Ebay.

One type there is no glass; the paper is held just my vacuum in place. <BR><BR>the other has a glass; that is used to hold both negative and paper in contact. This type can have holes; OR a radial set of valleys; heading towards the center of the frame. There is also a vacuum seal al the edge for the glass to seal against.