Abstract: Scanner, method or computer program product, arranged to sense media color information, store predetermined color values of preselected non-printed media and storing corresponding color profiles adapted for the respective preselected media, and process sensed color values, compare a sensed color value with the predetermined color values, and select one of said color profiles based on the comparison.

Abstract: Method of computing a convex hull in a predetermined color space, comprising determining a print attribute value range pertaining to a reference print attribute value, selecting base NP (Neugebauer Primary) area coverages, comprising area coverages of single NPs and combined NPs, having print attribute values in the print attribute value range, printing and measuring patches corresponding to the base NP area coverages, computing linear combinations of the base NP area coverages, and assigning one of the base NP area coverage or the linear combination of base NP area coverages to the corresponding color, depending on which is closest to the reference print attribute value.

Abstract: A method of printing using variable pixel replication factors involves generating from an input image a reference image and a plurality of half-tone source images generated at different resolutions of the input image and with post-halftoning pixel replication factors applied such that the half-tone source images are all the same size. A pixel-replication factor selector function is applied to each reference pixel of the reference image to determine a respective source image for that reference pixel. Thus, different reference pixels correspond to different pixel replication factors. A print-state image is assembled by applying to each print-state image pixel the print state of the corresponding source pixel in the corresponding source image. The print-state image is then printed to a print medium.

Abstract: The disclosure describes methods for color printing, performing a color separation process and performing a halftoning process. Furthermore, the disclosure describes the color separation process determining one or more Neugebauer Primaries, tessellating the Neugebauer Primaries, and generating one or more Neugebauer Primary area coverage vectors, whose area coverages are linear with respect to a device-independent color space. The disclosure further describes that the color separation process communicates with the halftoning process using one or more Neugebauer Primary area coverage vectors.

Abstract: Scanner, method or computer program product, arranged to sense media color information, store predetermined color values of preselected non-printed media and storing corresponding color profiles adapted for the respective preselected media, and process sensed color values, compare a sensed color value with the predetermined color values, and select one of said color profiles based on the comparison.

Abstract: Method of computing a convex hull in a predetermined color space, comprising determining a print attribute value range pertaining to a reference print attribute value, selecting base NP (Neugebauer Primary) area coverages, comprising area coverages of single NPs and combined NPs, having print attribute values in the print attribute value range, printing and measuring patches corresponding to the base NP area coverages, computing linear combinations of the base NP area coverages, and assigning one of the base NP area coverage or the linear combination of base NP area coverages to the corresponding color, depending on which is closest to the reference print attribute value.

Abstract: A print control system adapted to control a digital printer having a first machine-readable ink of a first colour and a second ink that is not machine readable at the same wavelength as said first ink and that is of substantially the same colour, said system being adapted to control said printer to print upon a document in said first ink a position—determining pattern readable by a digital pen to enable said pen to acquire data to enable a position of said pen in said pattern to be determined, and to print human discernable content that is not read by said pen superposed with said pattern using said second ink and not said first ink.

Abstract: The disclosure describes methods for color printing, performing a color separation process and performing a halftoning process. Furthermore, the disclosure describes the color separation process determining one or more Neugebauer Primaries, tessellating the Neugebauer Primaries, and generating one or more Neugebauer Primary area coverage vectors, whose area coverages are linear with respect to a device-independent color space. The disclosure further describes that the color separation process communicates with the halftoning process using one or more Neugebauer Primary area coverage vectors.

Abstract: A color-separation LUT and/or algorithm method and apparatus preferably convert input device-color data to output device-colorants, for many color-presentation types—automatically and for arbitrary colorant-set. In one major aspect of the invention, a device-hue ring is defined along six straight edges of a cubical device-hue space (without segments ending at white and black). Preferably coordinates defined along the six segments parametrize the procedure and equipment, i. e. establish colorant indexing by those coordinates (and preferably device-hue). In a second major aspect, plural color transformations—having respective favorable and adverse characteristics—serve different portions of input color space; their outputs merge to combine favorable properties of the transforms. In a third, cusps of the colorant hue planes populate the output side of the hue ring. In a fourth, a colorant sampling technique (faster by several orders of magnitude than exhaustive sampling) canvasses the output space.

Abstract: In one embodiment, a print system includes an anticipated ambient lighting selector to allow selection of an anticipated ambient lighting. A rendering module is configured to map a print job into raster data configured to reduce color cast in gray output when displayed under the anticipated ambient lighting.

Abstract: A method is provided of reproducing continuous tone pixel colors of a color image having many pixels based on Kueppers' device states, wherein the Kueppers' device states of a printing device are the printed pixel colors that are allowed based on Kueppers' color separation and halftoning. The method includes selecting a Kueppers' device state in the proximity of a continuous tone pixel color to be reproduced from the printing device's set of Kueppers' device states, and printing the Kueppers' device state. An error is diffused between the continuous pixel color and the selected Kueppers' device state to one or more pixels in the neighborhood.

Abstract: CDE is measured for each nozzle array, to enable modification of a mapping between input image data and intended printing marks to compensate for the CDE. Printing proceeds using the modified mapping, which is either an optical-density transformation of data to printing marks or a spatial-resolution relation between image data and intended pixel grid. The density transformation preferably includes a dither mask (but can be error-diffusion thresholding instead); the resolution relation includes scaling of image data to pixel grid. For some invention forms, CDE includes printing-density defects, measured and used to derive a correction pattern—in turn used to modify halftone thresholding. For other forms CDE includes swath-height error, but still this is measured and used to derive a correction pattern etc. For still other forms, however, CDE includes swath-height error and correction takes the form of scaling.

Abstract: A method of generating a device color profile for printing, with a printing device, on a translucent or transparent media. It includes: printing a profiling target on the media; measuring color values produced by the profiling target, when illuminated in transmission and when illuminated in reflection, in a device-independent color space; combining the transmission and reflection color values into combined transmission-reflection color values and creating a combined transmission-reflection profile mapping color values from a device-dependent color space to the device-independent color space; reversing the combined transmission-reflection profile, thereby obtaining the device color profile. The device color profile maps color values from a device-independent color space to a device-dependent color space in a manner which represents a color-reproduction compromise between transmission and reflection.

Abstract: A method of applying a gray neutrality calibration to a color signal, said method comprising: representing said color signal as a position in a multi dimensional color space, in which each said dimension of said color space represents a respective primary color; defining a gray axis in said multi dimensional color space as a set of coordinates for which a plurality of said primary colors each have a same value as each other; determining a distance between said position representing said color signal and said gray axis; and using said determined distance between said color signal position and said gray axis to apply a gray neutrality correction to said input color signal.

Abstract: A print control system adapted to control a digital printer having a first machine-readable ink of a first colour and a second ink that is not machine readable at the same wavelength as said first ink and that is of substantially the same colour, said system being adapted to control said printer to print upon a document in said first ink a position -determining pattern readable by a digital pen to enable said pen to acquire data to enable a position of said pen in said pattern to be determined, and to print human discernable content that is not read by said pen superposed with said pattern using said second ink and not said first ink.

Abstract: There is disclosed a method of dynamic generation of a linearized halftone matrix from a high bit resolution halftone matrix, for use in a printer device, for example a domestic or office printer device or a commercial high resolution printer device. A high bit resolution halftone threshold matrix is converted into a vector format (700). A tone correction function is applied by selecting a variable number of index values, each index value representing a threshold level. A tone corrected two-dimensional 8 bit threshold level matrix, is then applied to a corresponding print image plane comprising a plurality of pixels to obtain a two dimensional print data for each of a plurality of colors of an image. The print data is printed as a plurality of dots by a print head to form a printed image using a halftoning method.

Abstract: A direct device-space-to-device-space transform adjusts the amount of actual black ink, to avoid highlight and midtone granularity in incremental printing—but with no need for translation into perceptual space. If the amount of black ink specified in the input data for a particular color is very small or very large, then that specified color is passed through the transform without substantial change. Thereby the amount of actual black ink and other colorants is held as nearly as practical at levels dictated by device-space input specifications while minimizing visible granularity. Replacement behavior is chosen to smoothly blend between different kinds of operation in different tonal ranges. This system accommodates personnel trained in classical printing-press technologies, who are accustomed to full control over amounts of black and other colorants.

Abstract: A printing system is linearized automatically using measurements made with a simple optical sensor, such as a line sensor, that is onboard the system. The printing system itself is for forming images on plural printing media. Because the optical sensor is not a calorimeter or even a true densitometer, the sensor requires calibration, preferably based upon measurements using real inks. In the past it has been considered a requirement that such calibration be performed separately using each of the print media that was to be used for printing images. Linearization according to the invention, however, refers to a single calibration of the sensor, that calibration being used in common for essentially all media—even though the single calibration is performed with respect to exclusively a single one of the plural media.

Abstract: A number of sets of color values for an imaging system to output a corresponding number of neutral gray outputs at different lightness levels, is computed by interpolation, based at least in part on received or taken measurements of a number of near-neutral patches for the different lightness levels printed by the imaging system using a number of sets of color values of the imaging system's color space. The color values of the imaging system's color space are derived based on a number of sets of color values of a profile connection space (PCS) in accordance with a print table of a color profile of the imaging system mapping color value sets from the PCS to color value sets in the imaging system's color space. The various sets of defining color values define the near-neutral patches in the PCS.

Abstract: A method of applying a gray neutrality calibration to a color signal, said method comprising: representing said color signal as a position in a multi dimensional color space, in which each said dimension of said color space represents a respective primary color; defining a gray axis in said multi dimensional color space as a set of coordinates for which a plurality of said primary colors each have a same value as each other; determining a distance between said position representing said color signal and said gray axis; and using said determined distance between said color signal position and said gray axis to apply a gray neutrality correction to said input color signal.