Patent ID: 7555160

Claim:
A method for illustrating to choosers of colour by compensating for shifts in human perception of colour which occur when a colour initially perceived as a small colour sample is then perceived extending over a large surface area wherein the method comprises the steps of: a) providing an illustration means which allows the colours to be incorporated into a computer-manipulatable digital image of a room so that a true colour can be displayed and the image can be manipulated to display the appropriate shifted colour, wherein the illustration means includes carrier means and a plurality of pairs of colours carried by the carrier means and where each pair comprises a first colour present on the carrier means as a small colour sample and a second colour present on the carrier means as a small colour sample which second colour sample is adjacent the first colour sample, b) obtaining the true CIELAB lightness value L u * and the CIELAB chroma value C u * of the colour of the first small colour sample, c) choosing a second colour of hue similar to the hue of the first small colour sample which second colour has CIELAB lightness and chroma values L s * and C s * where L u * = - β L + { β L 2 + 4 ⁢ β L ⁡ [ 100 ⁢ ( 1 - 100 ⁢ ⁢ α L - β L ) - L s * ] } 1 / 2 2 ⁢ ⁢ α L and C u ⁢ ⁢ t * = - β C + { β c 2 + 4 ⁢ α C ⁢ C s * } 1 / 2 2 ⁢ ⁢ α C in which α L is from −0.007 to −0.0001 β L is from 0.8 to 1.5 α C is from −0.01 to −0.03 β c is from 2 to 2.3 d) imparting the second colour to the large surface area whereby because of the shift in human perception, the second colour when imparted to the large surface area is perceived by the human mind as being acceptably similar to the colour of the small colour sample wherein the above steps are implemented using the computer.