Abstract: Apparatus and method for contact printing uses a vacuum contact plate and a screen frame to hold a master film sheet in contact registration with a screen having a region that is substantially porous to the passage of air disposed about a central photosensitive region. The vacuum contact plate receives the screen frame and supports the master film sheet and the screen on an elevated, substantially planar component. Air is evacuated from a hollow cavity within the elevated component to create a pressure differential across the master film sheet to urge the master film sheet in contact with the screen. If the master film sheet is not large enough to cover the entire porous region of the screen, the master film sheet is attached to a carrier sheet of sufficient size. The carrier sheet is then placed on the elevated component to be retained in contact registration with the photosensitive screen.

Abstract: The apparatus and method of the present invention uses a register light unit to facilitate manual alignment of master photographic images on a flexible carrier sheet. The carrier sheet and master images are positioned relative to a photosensitive screen using a vacuum contact plate that receives a screen frame in tight registration using a substantially planar surface for supporting the flexible carrier sheet with master images thereon. Vacuum is drawn around the screen to develop a pressure differential across the carrier sheet to urge the master images thereon into surface contact with the photosensitive screen during exposure to a source of illumination. Work stations include storage bins for prepared screens and master films to expedite processing through an exposure unit that includes a vacuum contact plate which is mounted to translate between a load/unload position outside of a housing and an exposure position inside of a housing that shields an operator from radiation from the source of illumination.

Abstract: Improved method and apparatus for supporting photographic sheet materials in intimate surface contact during contact exposure includes a flexible membrane which forms a common boundary wall between two gas-tight chambers. Air at ambient pressure is admitted to one chamber at a controlled rate slower than air is evacuated from the other chamber containing the photographic sheet materials. Progressive expansion of the surface area of contacting force assures that residual volumes of air between photographic sheets are squeezed out in an orderly pattern and not trapped in isolated pockets that distort resulting photographic images. A dimensionally stable blanket is supported about the perimeter to slide in a retaining frame against resilient cushioning that urges the blanket into engagement with the platen.

Abstract: Improved method and apparatus for supporting photographic sheet materials in intimate surface contact during contact exposure includes a flexible membrane which forms a common boundary wall between two gas-tight chambers. Air at ambient pressure is admitted to one chamber at a controlled rate slower than air is evacuated from the other chamber containing the photographic sheet materials. Progressive expansion of the surface area of contacting force assures that residual volumes of air between photographic sheets are sneezed out in an orderly pattern and not trapped in isolated pockets that distort resulting photographic images.

Abstract: Improved method and apparatus for supporting photographic sheet materials in intimate surfact contact during contact exposure includes a flexible membrane which forms a common boundary wall between two gas-tight chambers. Air at ambient pressure is admitted to one chamber at a controlled rate slower than air is evacuated from the other chamber containing the photographic sheet materials. Progressive expansion of the surface area of contacting force assures that residual volumes of air between photographic sheets are squeezed out in an orderly pattern and not trapped in isolated pockets that distort resulting photographic images.

Abstract: Improved method and means are disclosed for holding sheets in registration during photographic exposure on a light table. An impervious blanket is rolled out from and into a housing which travels over the sheets positioned on the light surface to be selectively secured and sealed in place for vacuum gripping of sheets between blanket and light table.