A 3D printing system applies colored powders (e.g., primary colors, white, black, cyan, magenta, yellow, fluorescent colors, metallic) in printed polymer layers for forming a colored 3D object. The system may stabilize a powder layer or color sub-layers thereof, for example with one or more of heat, pressure, and/or high-intensity light. On each layer, powders of various colors may be sequentially deposited in a halftone pattern and stabilized, so as to create a part with a specified arrangement of colors throughout its structure. Benefits include more stable color than strategies involving jetting colored fluids. The arrangement of color on the interior of the part could provide functional or traceability benefits for specific applications. The examples allow for depositing a greater quantity of powder on each fiber base or substrate, decreasing the ratio of fiber to powder and increasing production speed.

The present disclosure aims to provide a high quality image without conspicuous graininess and density unevenness. An embodiment of the present invention is an apparatus for printing a plurality of dot patterns on a printing medium, the dot patterns being formed by substantially same color and substantially same dot diameter, the apparatus including: a first creation unit configured to create, based on a first tone value, a first dot pattern and a second dot pattern printed and superimposed on the first dot pattern; and a second creation unit configured to create, based on a second tone value larger than the first tone value, a third dot pattern having an equal or larger number of dots compared to the first dot pattern and a fourth dot pattern printed and superimposed on the third dot pattern and having an equal or larger number of dots compared to the second dot pattern.

Multiple first gradation values corresponding respectively to the multiple inks are quantized to generate multiple first quantized values indicating printing or non-printing of dots with the respective inks. In this case, multiple second gradation values corresponding respectively to multiple multinary colors expressible by combinations of overlapping of the multiple inks are generated based on the first gradation values. Next, the multiple second gradation values are quantized to generate multiple second quantized values indicating printing or non-printing of dots of the respective multinary colors. Then, the first quantized values corresponding to the inks to be overlapped one on top of another to express the multinary colors are generated based on the second quantized values corresponding respectively to the multiple multinary colors.

An apparatus comprises a unit configured to generate gradation data corresponding to an achromatic color generated by combining two or more colors among a plurality of colors, for an excess amount of a total gradation value exceeding a predetermined value, the total gradation value being a sum of gradation values of the plurality of colors used for recording a pixel of interest, and generate gradation data corresponding to the plurality of colors, based on the generated gradation data corresponding to the achromatic color; and a unit configured to quantize the generated gradation data, and generate data to control recording of dots corresponding to the pixel of interest. The predetermined value is a gradation value indicating whether or not to record the dots in an overlapping manner, in case that the dots corresponding to the total gradation value are recorded.

Certain examples described herein relate to color spaces. In some cases, data representing a set of color values is obtained. Each color value has, for each of first, second and third axes defining a three-dimensional color space, a respective coordinate value. In some cases, for each of the set of color values, the coordinate value for the first and/or second axis is transformed dependent on the coordinate value for the third axis, to generate data representing a transformed set of color values. A set of output color values in an output color space is derived using the generated data. Output data associating the set of output color values in the output color space with a set of further color values in a further color space is generated.

Certain examples described herein relate to color spaces. In some cases, data representing a set of color values is obtained. Each color value has, for each of first, second and third axes defining a three-dimensional color space, a respective coordinate value. In some cases, for each of the set of color values, the coordinate value for the first and/or second axis is transformed dependent on the coordinate value for the third axis, to generate data representing a transformed set of color values. A set of output color values in an output color space is derived using the generated data. Output data associating the set of output color values in the output color space with a set of further color values in a further color space is generated.

A method of processing data for additive manufacturing of a 3D object comprises: receiving graphic elements defining a surface of the object, and an input color texture to be visible over a surface of the object; transforming the elements to voxelized computer object data; constructing a 3D color map having a plurality of pixels, each being associated with a voxel and being categorized as either a topmost pixel or an internal pixel. Each topmost pixel is associated with a group of internal pixels forming a receptive field for the topmost pixel. A color-value is assigned to each topmost pixel and each internal pixel of a receptive field associated with the topmost pixel, based on the color texture and according to a subtractive color mixing. A material to be used during the additive manufacturing is designated based on the color-value.

An image processing apparatus is equipped with: an image data receiving unit that receives image data; and a print data generating unit that generates multiple value data as print data by performing a halftone process on the image data and converting the image data into at least three values. The print data generating unit administers a halftone process that includes a density fluctuation suppressing process that results in the print data always including a zero value except for a case in which all of the pixels that constitute the image data are converted into a maximum value.

In a data generating apparatus, a processor acquires offset information indicating a deviation in a colorant usage used by a specific print execution unit from a standard amount of usage. The standard amount of usage is a standard quantity concerning colorant used by print execution units. The processor controls the specific print execution unit to print a first patch image and generates first control data using first read data based on the first patch image. The processor generates corrected first control data using the offset information. The processor controls the specific print execution unit to print a second patch image using the corrected first control data and generates second control data using second read data based on the second patch image. The first and second control data is for common use in the printing processes performed on the print execution units.

In a data generating apparatus, a processor acquires offset information indicating a deviation in a colorant usage used by a specific print execution unit from a standard amount of usage. The standard amount of usage is a standard quantity concerning colorant used by print execution units. The processor controls the specific print execution unit to print a first patch image and generates first control data using first read data based on the first patch image. The processor generates corrected first control data using the offset information. The processor controls the specific print execution unit to print a second patch image using the corrected first control data and generates second control data using second read data based on the second patch image. The first and second control data is for common use in the printing processes performed on the print execution units.