Devices and methods for offset and similar printing systems
OwnerYoel Netz, Arnold Hoffmaninventors
Life of this patent
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Abstract
A method for producing a half-tone image faithfully representing a continuous-tone original includes a step of forming in the image a pattern of substantially continuous, substantially parallel lines at a frequency of between about 100 and 400 lines per inch, such that the width of the lines at a given point in the image varies in relation to the optical density of at least one color component at a corresponding point in the continous-tone original. The method may be used for color separations with each separation produced by scanning at a different angle. The method may be implemented using photomechanical or electronic scanning techniques.
Claims13
A method for producing a color image that is not continuous-tone but faithfully represents a continuous-tone color original comprising the steps of:
- (a) producing a first image that is not continuous tone and corresponds to a first color component of the continuous-tone color original, by forming in said first image an electronically generated pixel pattern creating substantially continuous, substantially parallel lines at a frequency of between about 100 and 400 lines per inch, such that the width of each one of said lines at a given point in the first image varies in relation to the optical density of said first color component at a corresponding point in the continous-tone original, said substantially parallel lines in said first image having a first line frequency, and said substantially parallel lines in said first image defining a first direction;
- (b) producing a second image that is not continuous tone and corresponds to a second color component of the continuous-tone color original, by forming in said second image an electronically generated pixel pattern creating substantially continuous, substantially parallel lines at a frequency of between about 100 and 400 lines per inch, such that the width of each one of said lines at a given point in the second image varies in relation to the optical density of said second color component at a corresponding point in the continuous-tone original, said substantially parallel lines in said second image having a second line frequency substantially equal to said first line frequency, and said substantially parallel lines in said second image defining a second direction rotated from said first direction;
- (c) producing a third image that is not continuous tone and corresponds to a third color component of the continuous-tone color original, by forming in said third image an electronically generated pixel pattern creating substantially continuous, substantially parallel lines at a frequency of between about 100 and 400 lines per inch, such that the width of each one of said lines at a given point in the third image varies in relation to the optical density of said third color component at a corresponding point in the continuous-tone original, said substantially parallel lines in said third image having a third line frequency substantially equal to said first line frequency, and said substantially parallel lines in said third image defining a third direction rotated from both said first direction and said second direction;
- wherein said producing of each of said first, second and third images comprises scanning an image carrier with one or more directly exposing scanning beams;
- and
- (d) combining said first, said second and said third images in registration to thereby produce said color image that is not continous tone but faithfully represents the continuous tone color original.
Dependencies are inferred from the claim text.