A method for selecting a colorant amount for printing is described in which a maximum optical density of an image is identified. The maximum optical density is compared to with a threshold optical density, and when the threshold is exceeded, dot cluster sizes from a first lookup table are selected, otherwise, dot cluster sizes from a second lookup table are selected. A colorant thickness corresponding to the selected dot cluster sizes is selected for printing the image.

The spectral colorimetry apparatus includes an LED, a diffraction grating; a line sensor that has multiple pixels and that receives light dispersed by the diffraction grating at the multiple pixels for respective wavelengths of the dispersed light and outputs voltages according to the intensity of the received light; and a sensor CPU that calculates spectral reflectivity of an object based on the intensity of light reflected from the object. The sensor CPU varies, with the multiple pixels, the number of detection times of detecting the light reflected from the object at each pixel.

White-balance is improved when printing on colored media, while minimizing the time and use of costly materials required by present approaches. In an embodiment, the typical solid white fill or background layer is altered by including in the white layer one or more of the other colors already available in the printer to shade this layer. Thus, a small amount of cyan, for example, helps balance a pink-ish (red) media; yellow is used for blue media; and magenta is used for green media; as well as combinations thereof. A combination of transparent process inks and opaque white helps to maintain brightness (luminosity).

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.

Threshold values in a dither matrix according to the present invention are arranged such that in a case where screen processing is executed on a multi-tone image that has a first density, halftone dots are formed at a first screen angle, and in a case where screen processing is executed on a multi-tone image that has a density being higher than a second density that is higher than the first density, halftone dots are formed at a second screen angle that is different from the first screen angle.

Systems, methods, and software for halftoning. In an embodiment, a halftone system is configured to store a threshold array comprising an array of threshold elements. The halftone system is further configured to receive a source image comprising an array of pixels with pixel values, and perform a multi-level halftoning process on the source image by partitioning the source image into a sequence of image segments, partitioning the threshold array into a plurality of threshold segments, identifying image segment groups each comprising a set of the image segments that are noncontiguous in the sequence and correspond with a mutual threshold segment of the threshold array, and schedule processing of the image segments in an image segment group as a batch based on the mutual threshold segment.

In an error diffusion process, a control device determines a dot value of a target pixel by using a gradation value of the target pixel, and an error value. The control device determines distribution error value by comparing a gradation dependent value with a first evaluated density value indicating a density of a first dot. The control device determines the distribution error value by using the first evaluated density value when the dot value of the target pixel indicates formation of the first dot and when the gradation dependent value is smaller than or equal to the first evaluated density value. The control device determines the distribution error value by using a modified evaluated density value greater than the first evaluated density value when the dot value indicates formation of the first dot and when the gradation dependent value is greater than the first evaluated density value.

A image forming system of the present inventation includes a control section that causes a pattern image for image density control to be formed on an image carrier, and performs density correction control for correcting a density of a formed image on the basis of density information on the formed pattern image for image density control, wherein the control section determines a timing for performing the density correction control, on the basis of information corresponding to a density difference generated between images formed by the plurality of image forming apparatuses.

An example embodiment may involve causing a page of a document to be printed on a printing device, wherein the printing device is in an AM halftoning mode and prints the page using an AM halftone; displaying, on the display unit, a graphical user interface, wherein the graphical user interface includes a selectable option to switch the printing device from the AM halftoning mode to an FM halftoning mode; receiving an indication that the selectable option has been selected; possibly in response to receiving the indication that the selectable option has been selected, causing the printing device to switch from the AM halftoning mode to the FM halftoning mode; and causing the page of the document to be printed again on the printing device, wherein the printing device is in the FM halftoning mode and prints the page using an FM halftone.

A colorant splitting method performed by a colorant splitter wherein an n-dimensional color in an n-dimensional colorant space is converted to an m-dimensional colorant space by a colorant splitting curve set and wherein the colorant splitting curve set is the result of interpolation of a set of colorant splitting curve sets to improve the image quality of reproduced content and to improve the usage of total coverage of the colorants.