Screen gravure engraving system for electromechanical engravers

A method for converting halftone and screened film for use with electromechanical gravure engravers, comprising the steps of:

• providing an array of photosensitive elements;
• arranging at least one film with image information thereon in the form of transparent and opaque picture elements (pixels) having predetermined dimensions relative to the array;
• assigning a predetermined number of photosensitive elements of the array to each pixel width of the film;
• sampling a predetermined length of the film corresponding to a predetermined number of pixel lengths;
• repeating the sampling of the predetermined length of the film a predetermined number of times to cover a predetermined outer area covering a plurality of pixels;
• counting the number of photosensitive elements which detect transparent portions within the predetermined outer area;
• counting the number of photosensitive elements which detect transparent portions bounded by an inner predetermined area including a plurality of pixels and having its center coincident with the center of the predetermined outer area;
• and
• providing a signal representing an enhanced percentage dot area (PDA) per pixel by adding the count of the inner predetermined area to the count of the inner predetermined area minus the count of the outer predetermined area, such PDA signal being adaptable for use by an electromechanical engraver to engrave gravure cells of the desired volume in a gravure cylinder.

System for converting halftone and screened film for use with electromechanical gravure engravers, comprising:

• an array of photosensitive elements for scanning the film;
• rotatable means positioned adjacent the array and having mounted thereon at least one film having an image thereon in the form of transparent and opaque picture elements (pixels) having predetermined dimensions;
• first gating means for counting a first predetermined number of photosensitive elements during each scan, the first predetermined number of photosensitive elements corresponding to the width of a plurality of pixels;
• second gating means for counting a second predetermined number of photosensitive elements during each scan, the second predetermined number of photosensitive elements corresponding to the width of a plurality of pixels having a total width less than the first predetermined number of photosensitive elements;
• counter means for determining the number of samples per pixel length and thereby establishing in conjunction with said first and second counting means first and second predetermined sampled areas;
• and
• means for providing a signal representing an enhanced percentage dot area (PDA) including a portion of the count of the second predetermined sampled area minus a portion count of the first predetermined sample area as determined by the number of pixels covered by the second and first predetermined sample areas.