Visually assessed colour description including the luminance of the background

In many technical areas of the colouring industry, like printing, textile- and automotive industry, colouring is controlled by colour measurement and colour-difference evaluation. However, colour- difference formulae used in practice are not well adapted to human perception. There are two formulas presented which calculate the colour differences better adapted to human perception. Both formulas correct the CIE-76 formula. One of this formulas has the advantage, that it is very simple. That's why measurement results can be corrected in a simple way after measurement. There is another formula given which allows including the luminance of the background in the colour measurement. So far the luminance of the background was out of consideration by colour measurement, although the background is very important in colour vision.