Clustering colors for halftoning

A method of configuring a halftoning operation for a color rendering device, comprising:

• determining a set of output color states that are renderable by the color rendering device using a set of colorants;
• obtaining color measurements for the set of output color states;
• grouping the set of output color states into clusters based on the color measurements;
• determining an order for output color states within the clusters based on colorant composition;
• and
• outputting configuration data for the halftoning operation indicative of the order.

A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to:

• receive color data for an image to be rendered by a color rendering device, the color data indicating probability values for output color states for input image areas corresponding to portions of a rendered output, the output color states being renderable by the color rendering device using a set of colorants;
• retrieve configuration data indicating an order of output color states for application of a halftone matrix, the output color states being grouped in clusters based on measured color properties associated with the color rendering device, the order within the clusters being based on colorant composition;
• and
• apply a halftone matrix to the color data to generate render data for the color rendering device, including, for a given portion of the rendered output, to select an output color state for the given portion by sampling the color data using the order indicated in the configuration data, wherein values of the halftone matrix correspond to thresholds for the sampling.