Abstract: An output color profile, such as an ICC output profile, contains a look-up table to separate the color of a pixel, for example a CIELAB color, into a set of colorant values, for example CMYK colorants. In practice, most CMYK images have been separated using one of a limited set of standardized output profiles. The problem to be solved is guessing which one of these standardized output profiles has been used to separate a specific image. For this purpose the CMYK values of the image are analyzed. The analysis involves calculating a distance in the CMYK space between the CMYK values of an image, and the CMYK values produced by different output profiles. A profile is selected based on these distances, for example by selecting the profile yielding the shortest distance. This profile is then used for converting the CMYK colorant values of the image into CIELAB color values.

Abstract: A method and apparatus for creating a print file for printing a 3-D print using a 3-D printing system is described, the 3-D print comprising a plurality of 3-D structures printed on a substrate, each 3-D print structure having a height with respect to the substrate. A two-dimensional source image is input comprising a plurality of image pixel areas. A filtered image is obtained by applying a topographic operator to the source image to generate for every image pixel a representation of a pixel height profile, the pixel height profile corresponding to cross-sections through a 3-D print structure which is to be formed by 3-D printing. Thereby definitions of a plurality of image layers are generated from the filtered image for printing using the 3-D printing system. The print file is output based on the plurality of image layers.

Abstract: An output color profile, such as an ICC output profile, contains a look-up table to separate the color of a pixel, for example a CIELAB color, into a set of colorant values, for example CMYK colorants. In practice, most CMYK images have been separated using one of a limited set of standardized output profiles. The invention deals with the problem of guessing which one of these standardized output profiles has been used to separate a specific image. For this purpose the CMYK values of the image are analyzed. The analysis involves calculating a distance in the CMYK space between the CMYK values of an image, and the CMYK values produced by different output profiles. A profile is selected based on these distances, for example by selecting the profile yielding the shortest distance.

Abstract: Printing masters are produced by use of an inkjet printing system. The smallest halftone dot size which can be printed by the inkjet printing system is larger than the size of a pixel of the recording grid defined by the addressability of the printing device. Inferior image quality and graininess caused by standard error diffusion algorithms in this system can be counteracted by using a constraint correlation error diffusion system. Out of the complete set of all possible intensity level combinations for reproducing a pixel a subset is selected based upon the multilevel halftoning process of a quantized scalar value which is a function of at least one of the input pixel values of the corresponding colour component pixels. Preferably the scalar value represents the brightness or ink amount allocations.

Abstract: Separation of a color into values for colorants in colorant space can be done easily when color correction and color separation are done in separate steps, where the color is defined as a set of values in a trajectory space, and trajectories include points for which ink behavior during color separation is known. Colorant values for the color are determined by interpolation using values of the color located in trajectory space, and known values and corresponding colorant values of the trajectory points. Trajectories are preferably color axes dividing the trajectory space into tetrahedral. Colorant values may be corrected using techniques such as colorant replacement or colorant splitting prior to color separation. The color separation process can be calibrated using a test target.

Abstract: The method reproduces an electronic image, having pixels, as a multilevel halftone image on a multilevel output device having N different allowed output values (possible density levels) by choosing for any pixel p a real subset Sp containing Np allowed values out of the set S of N allowed levels quantizing the input pixel value of the pixel p to obtain an output pixel value out of the Np values in Sp by means of a half toning algorithm, rendering the image by rendering the pixels with the output device using the obtained output pixel values. The real subset may be formed by the allowed output values closest to the input pixel value. The quantization may be done by an error diffusion algorithm The used method prevents occurrence of pixels having deviating densities distorting the output image.

Abstract: Printing masters are produced by use of an inkjet printing system. The smallest halftone dot size which can be printed by the inkjet printing system is larger than the size of a pixel of the recording grid defined by the addressability of the printing device. The error diffusion algorithm is especially adapted to make use of the high addressability of the recording system. Using a sub-dot phase modulated error diffusion halftoning algorithm allows for the distance between the halftone dots to be modulated in much smaller increments than the size of the halftone dots themselves. Results can be further improved by dynamically influencing the threshold value in the error diffusion algorithm in accordance with previous output quantisation determinations. Variable coverage percentage of the pixels can be taken into account. The method can be extended to multilevel systems.

Abstract: There is provided a method for making a lithographic printing plate from an original containing continuous tones comprising the steps of: screening said original to obtain screened data scan-wise exposing a lithographic printing plate precursor according to said screened data, said lithographic printing plate precursor having a surface capable of being differentiated in ink accepting and ink repellant areas upon said scan-wise exposure and an optional development step and optionally developing a thus obtained scan-wise exposed lithographic printing plate precursor, characterized in that said screening is a frequency modulation screening. The print results of a thus obtained printing plate can be previewed using simple proofing techniques.

Abstract: Method and apparatus for creating 3D-prints and a 3-D printing system A method and apparatus for creating a print file for printing a 3-D print using a 3-D printing system is described, the 3-D print comprising a plurality of 3-D structures printed on a substrate, each 3-D print structure having a height with respect to the substrate. A two-dimensional source image is input comprising a plurality of image pixel areas. A filtered image is obtained by applying a topographic operator to the source image to generate for every image pixel a representation of a pixel height profile, the pixel height profile corresponding to cross-sections through a 3-D print structure which is to be formed by 3-D printing. Thereby definitions of a plurality of image layers are generated from the filtered image for printing using the 3-D printing system. The print file is output based on the plurality of image layers.

Abstract: Printing masters are produced by use of an inkjet printing system.

Abstract: Printing masters are produced by use of an inkjet printing system.

Abstract: In an error diffusion halftoning process a clusters of adjacent pixels can be placed at any arbitrary position of the pixel grid.

Abstract: A multi-level printing process using a printer by converting electronic page data to multi-level bitmap data with a specific number of gradation levels Nlev at a specified spatial resolution higher than that of the printer; converting the multi-level bitmap data to a lower spatial resolution; reducing the number of gradation levels by a processing technique to some lower number Nlevp giving a second multi-level bitmap; and printing the multi-level output bitmap by a printer having at least Nlevp different gradation levels at a single pixel location.

Abstract: The method reproduces on an output device an electronic image having color pixels, each color pixel being represented by K spatially corresponding component pixels, K>1, each component pixel having an input pixel value, the output device being capable of rendering Nj intensity levels for a component pixel j, 1≦j≦K, thereby defining N1*N2* . . . *NK intensity level combinations, the method comprising the steps of: computing for any color pixel a scalar value which is a function of at least one of said input pixel values of said spatially corresponding component pixels; quantizing said scalar value by a multilevel halftoning process to obtain for said color pixel a quantized scalar value; using said quantized scalar value to select, out of all said intensity level combinations, a subset of intensity level combinations; selecting one combination out of said subset; using said selected combination for reproducing said color pixel by said output device.

Abstract: Separation of a color into values for colorants in colorant space can be done easily when color correction and color separation are done in a separate step.

Abstract: The method reproduces an electronic image, having pixels, as a multilevel halftone image on a multilevel output device having N different allowed output values (possible density levels) by

Abstract: There is provided a method for making a lithographic printing plate from an original containing continuous tones comprising the steps of:

Abstract: A frequency-modulation halftone screen and method for making same, utilizing local randomization of a deterministic screen. The deterministic screen optimizes uniformity of the halftone dot distribution, while the local randomization suppresses artifacts due to subject moiré.

Abstract: The method reproduces on an output device an electronic image having color pixels, each color pixel being represented by K spatially corresponding component pixels, K>1, each component pixel having an input pixel value, the output device being capable of rendering Nj intensity levels for a component pixel j, 1≦j≦K, thereby defining N1*N2* . . .

Abstract: A multi-level printing process using a printer includes the following four steps.