Computational Colour Science Using MATLAB, 2nd Edition

Chapter 11

Characterisation of Printers

11.1 Introduction

Physical models tend to play a more important role in the characterisation of printers than they do with other imaging devices. One reason for this is that the relationship between printer inputs and CIE tristimulus values is usually extremely nonlinear. In addition, however, there is a great deal of theory that has been developed for the prediction of the colour of printing inks from colourant concentration values in a wider context. The Kubelka-Munk theory, for example, has been used for more than half a century to predict spectral reflectance from colourant concentration values. Artificial neural networks have also been used quite widely to find mappings between vectors of colourant concentration values and spectral reflectance values. Numerous technologies are used in printers and this is another reason why different and specific models are used to characterise the devices. Most printers use three or four primaries: cyan, magenta, yellow and black. Note that the primaries of a subtractive colour mixing process are quite different from those (typically red, green and blue) for an additive colour mixing process. For both additive and subtractive devices the primaries are normally selected to enable the greatest gamut of colours to be reproduced. In a subtractive process, the intensities of the red, green and blue light in the print are indirectly controlled by the amount of the cyan, magenta and yellow ink deposited respectively. ...