A method of colouring a cosmetic covering, the method comprising: acquiring an image of a part of a human or animal body with an image acquisition apparatus to provide a digital colour image; characterised in that the method further comprises the steps of: acquiring an image of a colour chart with the image acquisition apparatus to provide a colour chart image; determining a calibration transform for colours of the image acquired by the image acquisition apparatus in dependence on the colour chart image and colour values represented in the colour chart, wherein the calibration transform includes transformations for each of Red, Green and Blue values and each Red, Green and Blue transformation includes a Look Up Table, wherein each LUT is determined by sparsely populating the LUT with colour differences between each of the colour values in the colour chart image and each corresponding actual colour for the colour chart and interpolating between the sparse points; transforming the digital colour image with the calibration transform to provide a colour compensated digital colour image; conveying at least one colour characteristic of at least one colour within the colour compensated digital colour image to a paint mixing apparatus, which is operative to mix a plurality of paints of different colours in dependence on the at least one colour characteristic to produce at least one mixed paint; and applying the at least one mixed paint to a cosmetic covering. acquiring an image of a part of a human or animal body with an image acquisition apparatus to provide a digital colour image; characterised in that the method further comprises the steps of: acquiring an image of a colour chart with the image acquisition apparatus to provide a colour chart image; determining a calibration transform for colours of the image acquired by the image acquisition apparatus in dependence on the colour chart image and colour values represented in the colour chart, wherein the calibration transform includes transformations for each of Red, Green and Blue values and each Red, Green and Blue transformation includes a Look Up Table, wherein each LUT is determined by sparsely populating the LUT with colour differences between each of the colour values in the colour chart image and each corresponding actual colour for the colour chart and interpolating between the sparse points; transforming the digital colour image with the calibration transform to provide a colour compensated digital colour image; conveying at least one colour characteristic of at least one colour within the colour compensated digital colour image to a paint mixing apparatus, which is operative to mix a plurality of paints of different colours in dependence on the at least one colour characteristic to produce at least one mixed paint; and applying the at least one mixed paint to a cosmetic covering. acquiring an image of a colour chart with the image acquisition apparatus to provide a colour chart image; determining a calibration transform for colours of the image acquired by the image acquisition apparatus in dependence on the colour chart image and colour values represented in the colour chart, wherein the calibration transform includes transformations for each of Red, Green and Blue values and each Red, Green and Blue transformation includes a Look Up Table, wherein each LUT is determined by sparsely populating the LUT with colour differences between each of the colour values in the colour chart image and each corresponding actual colour for the colour chart and interpolating between the sparse points; transforming the digital colour image with the calibration transform to provide a colour compensated digital colour image; conveying at least one colour characteristic of at least one colour within the colour compensated digital colour image to a paint mixing apparatus, which is operative to mix a plurality of paints of different colours in dependence on the at least one colour characteristic to produce at least one mixed paint; and applying the at least one mixed paint to a cosmetic covering.