Printer calibration

A printing system comprising:

• an interface to receive data indicating an adjustment to be applied to a given colorant in a set of colorants printable by the printing system;
• a memory comprising:
• a vector in an area coverage space, the vector defining a statistical distribution of an operating set of colorant combinations implementable by the printing system over an area of a halftone;
• and
• configuration data dependent on the operating set of colorant combinations, the configuration data mapping colorant adjustments to relationships between colorant combinations in the operating set of colorant combinations;
• and
• a print controller to:
• identify first and second subsets of the operating set of colorant combinations using the configuration data and the data indicating the adjustment;
• and
• modify the vector by decreasing a contribution to the vector of a colorant combination in the first subset and increasing a contribution to the vector of a colorant combination in the second subset,
• wherein the configuration data indicates a relationship between a given colorant combination in the first subset and a corresponding colorant combination in the second subset for an increase in the given colorant and for a decrease in the given colorant.

A non-transitory computer-readable storage medium comprising a set of computer-readable instructions that, when executed by a processor of a printing system, cause the processor to:

• receive adjustment parameters identifying a given printing fluid in a set of printing fluids useable by the printing system, the adjustment parameters indicating an adjustment to be applied to the given printing fluid;
• and
• calibrate the printing system by modifying a Neugebauer Primary area coverage (NPac) vector,
• wherein the instructions that cause the processor to calibrate the printing cause the processor to:
• determine configuration data dependent on an operating set of NPs implementable by the printing system, the configuration data mapping printing fluid adjustments to relationships between NPs in the operating set of NPs;
• use the configuration data and the adjustment parameters to identify first and second subsets of the operating set of NPs;
• and
• decrease an area coverage in the NPac vector of an NP in the first subset and complementarily increase an area coverage in the NPac vector of an NP in the second subset,
• wherein the configuration data indicates a relationship between a given NP in the first subset and a corresponding NP in the second subset for an increase in the given printing fluid and for a decrease in the given printing fluid.