Abstract: An apparatus and method of producing enhanced digital imaging for printing data, in flexographic and other types of printing environments, combines halftone screens which represent continuous "gray tone" (grey tone) levels, wherein the transition from one screen to the other is not visually detectable by an observer of the reproduction results. The digital processing method includes combining an (FM generated) dispersed dot screen with an (AM generated) cluster dot screen, with an overlay interval of both screens of acceptable resultant dot size (percent coverage), to obtain enhanced overall definition over the grey scale range of 1 to 100 percent (i.e., where 100 is equal to "255" in 8-bit environment), specifically over the more visually perceptive gray scale range of 1 to 20 (i.e., out of 0-255 value). The apparatus which implements the method algorithm is positioned intermediate a desktop publishing system and an image setter.

Abstract: A method for the nonlinear calibration of digital image data without the introduction of tonal loss is applied to image data in a computer-to-printing press system. Apparatus for implementing this method is provided. Computer processed graphics, provided from the computer in 8-bit format, are converted into 16-bit format. This 16-bit image data is then calibrated to compensate for anticipated press gain. The calibration translates the image data according to a desired nonlinear cutback (value reduction) curve of gray value reduction. Calibrated image data is then passed through 16-bit halftoning screening, the output from which is provided to the imagesetter. The implemention may include a general purpose computer with specific software resident therein, or dedicated hardware including a series of encoders and look-up table implementaion devices.

Abstract: An apparatus and method of producing enhanced digital imaging for printing data or reproduction process data (digital camera data) from the combination of dot size (amplitude) and dot density (frequency) halftone screens, whereof each halftone screen represents continuous "gray tone" (grey tone) input image levels. The method includes creating a dot frequency modulation (FM modulation--dispersed dot technique) in lighter areas which otherwise would require a dot size which is below user definable "dot size limit". This dot frequency modulation randomly deletes dots from the dot area modulation screen (AM modulation--cluster dot technique) in these lighter areas. The percentage of frequency modulation is graduated over the range of gray values which reduces objectionable visual transitions. Enhanced overall definition over the gray scale range of 0 to 100 percent (i.e., where 100 is equal to "255" in 8-bit environment), specifically over the more visually perceptive gray scale range of 0 to 20 (i.e.