Further adjusting the adjusted NPac vector comprises decreasing the area coverage in the adjusted NPac vector of the second NP and increasing the area coverage in the adjusted NPac vector of a third NP. The second NP and the third NP correspond to colorant combinations that differ by a further predetermined amount of the given colorant. The further predetermined amount may be the same as or different from the predetermined amount corresponding to the difference between the first NP and the second NP. For example, the further predetermined amount may comprise one drop of the given colorant. In some examples, the colorant combination corresponding to the first NP comprises a first amount of the given colorant, the colorant combination corresponding to the second NP comprises a second amount of the given colorant, and the colorant combination corresponding to the third NP comprises a third amount of the given colorant. For example, the colorant combinations corresponding to the first, second and third NPs may comprise three drops, two drops and one drop of the given colorant, respectively. In one example, where the given colorant is M, the colorant combinations corresponding to the first, second and third NPs are CMM, CM and C, respectively.

The method 300 may be repeated for other colorants in the set of colorants, and/or for other NPac vectors.

The adjusted NPac vector may be stored in a lookup table mapping colorimetric values with NPac vectors, e.g. a HANS lookup table. The color mapping represented by the HANS lookup table may be applied to print job data, for example in a printing operation performed by the printing system.