colour accuracy those colours which are inside the ink jet colour gamut 2 are prefectly reproduced those outside the ink jet colour gamut are 34 clamped 34 to the nearest points on the boundary referring now to fig3 there is shown the method of colour gamut matching utilised in the preferred embodiment where the strategy adopted is to optimise the mapping to make relative distances between different colours in the image remain the same the red r green g and blue b 34 corners 34 of the crt gamut 1 are mapped to the red r 39 green g 39 and blue b 39 corners of the ink jet gamut 2 this mapping is carried out regardless of the absolute colour values of these corners those colours in the interior of the crt gamut are mapped so as to preserve their relative differences from the r g and b corners as well as from each other for example in fig3 the point g is mapped to the point g 39 the point b is mapped to the point b 39 and the point r is mapped to the point r 39 additionally the point 10 is mapped approximately to the point 11 and the point 12 is mapped approximately to the point 13 referring now to.