An example system in accordance with an aspect of the present disclosure includes a halftone engine and a gray value engine. The halftone engine is to apply halftoning to an image recursively across a plurality of levels of image scales and spatial resolutions, to generate a pattern that is at least quasi-periodic across the plurality of levels. The gray value engine is to substitute gray values recursively for at least a portion of the halftoning.

An information processing apparatus, in accordance with rising density in an extreme density range, determines a threshold for setting each pixel of the threshold matrix so as to consecutively grow an isolated dot corresponding to a halftone dot in a low density range to a first dot size for each submatrix; sets, when the size of isolated dots in a predetermined number of submatrices is grown to the first dot size, an intermediate position between the isolated dots in the predetermined number of submatrices; and determines, for each of one or more submatrices including a set intermediate position, a threshold to set for each pixel of the threshold matrix so that an isolated dot is consecutively grown until a second dot size smaller than the first dot size.

For a multi-pass printing, an image of a unit area is printed by M printing scans of M print regions of first and second nozzle arrays. Each of N pieces of column data is printed by a different printing scan. Ejection data for the first nozzle array is generated using a first mask pattern and ejection data for the second nozzle array is generated using a second mask pattern different from the first mask pattern, for each of the N pieces of column data. On that basis, the first mask pattern and the second mask pattern have a complementary relationship in each of the M print regions. Further, in each of the first mask pattern and the second mask pattern, a combination of print regions, of the M print regions, for printing dots at the same position on the print medium has a mutually complementary relationship.

A system, method, and non-transitory computer readable medium are disclosed for mitigating dot placement errors for a given print job. The method includes processing tone values on a per pixel basis to determine whether to implement plane dependence. Plane independence is implemented if the tone value exceeds a predetermined threshold. The method may be performed on a pixel by pixel basis and/or a print object or region basis. Determining whether to implement plane dependence may involve de-asserting or partially de-asserting a plane dependence component of an executed half-toning instruction between sequentially processed color planes of a printing system.

A flexographic printing plate includes at least one halftone printing area with a plurality of halftone dots. A halftone dot of said plurality of halftone dots is shaped as a relief area. Said relief area includes a central portion and a surrounding portion. Said central portion has a central dot floor with a first pattern of a plurality of pins protruding upwardly from the central dot floor. Said surrounding portion protrudes upwardly from the central dot floor and has a top side including a second pattern of a plurality of recesses. The first pattern and second pattern are such that the surrounding portion can be distinguished from the central portion.

A computer-implemented method for generating an amplitude modulated multi-cluster halftone dot for use in an amplitude modulated screen includes determining an arrangement of clusters within the dot; determining a cluster function for each cluster, the cluster function defining a pixel sequence indicating a sequence of turning on device pixels within an area of a particular cluster; determining a dot function for the dot, the dot function defining a cluster sequence indicating a sequence of the clusters; and generating a set of data representative of the dot for a particular tonal value, by determining the device pixels within the dot turned on for that particular tonal value according to the cluster functions and the dot function. A computer program, a printing device and a printed product are also provided.

In one example, halftone data comprising first data and second data representing a plurality of pixels in a halftone is generated. The first data associates a first subset of the plurality of pixels in the halftone with a first colorant, the first subset defining a first region in the halftone. The second data associates a second subset of the plurality of pixels in the halftone with a second colorant different from the first colorant, the second subset defining a second region in the halftone. The first subset of the plurality of pixels in the halftone and the second subset of the plurality of pixels in the halftone are mutually exclusive, and the first region is at least partially enclosed by the second region.

In order to obtain a smooth gradation reproduction in an image to be formed, an image processing apparatus inputs first data of an image to be formed which includes a color and second data of the image to be formed which does not include the color and has continuous gradation; determines printing material amount data corresponding to the first data; determines, based on the printing material amount data, a dot pattern when forming the image by performing a printing scan a plurality of times on a printing medium; and generates, based on the second data, a switching signal that switches each pixel in accordance with an area ratio of each of a first dot pattern and a second dot pattern.

A technique capable of keeping image quality and speeding up a halftone process is provided. An image processing device performs the halftone process on image data in which a pixel has a pixel value conforming to a bit count N. Bits conforming to the bit count N include higher H bits (where H is an integer satisfying an inequality of 1H<N) and lower L bits following the higher H bits (where L is an integer satisfying an inequality of 1LNH). The image processing device includes a first halftone processing unit configured to generate dot data indicative of a formation state of a dot, with respect to a first pixel allowing a determination of a formation state of a dot, based on the higher H bits in the pixel value and higher H bits in a dither mask.

A flexographic printing plate includes at least one halftone printing area with a plurality of halftone dots. A halftone dot of said plurality of halftone dots is shaped as a relief area. Said relief area includes a central portion and a surrounding portion. Said central portion has a central dot floor with a first pattern of a plurality of pins protruding upwardly from the central dot floor. Said surrounding portion protrudes upwardly from the central dot floor and has a top side including a second pattern of a plurality of recesses. The first pattern and second pattern are such that the surrounding portion can be distinguished from the central portion.