Devices and methods for offset and similar printing systems
First Claim
1. A method for producing a color image faithfully representing a continuous-tone color original comprising the steps of:
- (a) producing a first half-tone image corresponding to a first color component of the continuous-tone color original, by forming in said first half-tone 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 said lines at a given point in the image varies in relation to the optical density of said first color component at a corresponding point in the continuous-tone original, said substantially parallel lines in said first half-tone image having a first line frequency, said substantially parallel lines in said first half-tone image defining a first direction;
(b) producing a second half-tone image corresponding to a second color component of the continuous-tone color original, by forming in said second half-tone 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 said lines at a given point in the 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 half-tone image having a second line frequency substantially equal to said first line frequency, said substantially parallel lines in said second half-tone image defining a second direction rotated from said first direction;
(c) producing a third half-tone image corresponding to a third color component of the continuous-tone color original, by forming in said third half-tone 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 said lines at a given point in the 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 half-tone image having a third line frequency substantially equal to said first line frequency, said substantially parallel lines in said third half-tone image defining a third direction rotated from both said first direction and said second direction; and
(d) combining said first, said second and said third half-tone images in registration.
1 Assignment
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Accused Products
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 continuous-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.
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Citations
5 Claims
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1. A method for producing a color image faithfully representing a continuous-tone color original comprising the steps of:
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(a) producing a first half-tone image corresponding to a first color component of the continuous-tone color original, by forming in said first half-tone 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 said lines at a given point in the image varies in relation to the optical density of said first color component at a corresponding point in the continuous-tone original, said substantially parallel lines in said first half-tone image having a first line frequency, said substantially parallel lines in said first half-tone image defining a first direction; (b) producing a second half-tone image corresponding to a second color component of the continuous-tone color original, by forming in said second half-tone 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 said lines at a given point in the 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 half-tone image having a second line frequency substantially equal to said first line frequency, said substantially parallel lines in said second half-tone image defining a second direction rotated from said first direction; (c) producing a third half-tone image corresponding to a third color component of the continuous-tone color original, by forming in said third half-tone 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 said lines at a given point in the 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 half-tone image having a third line frequency substantially equal to said first line frequency, said substantially parallel lines in said third half-tone image defining a third direction rotated from both said first direction and said second direction; and (d) combining said first, said second and said third half-tone images in registration. - View Dependent Claims (2, 3, 4, 5)
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Specification