1. A method for recognition of hues wherein a color surface is illuminated with light having a known spectral composition and intensities of three primary colors in received light are opto-electronically measured as measured color values which represent color coordinates of corresponding color loci in an RGB color space, wherein the measured color values are converted into chrominance and luminance values as color coordinates of corresponding color loci in a chrominance/luminance color space by means of a color space transformation, and wherein a hue recognition region is defined within the color space and the measured color loci or their color coordinates are checked as to whether they fall into the defined recognition region or not, comprising the steps of: (a) before the actual hue recognition determining a color locus F.sub.0 of a hue T.sub.0 to be recognized by color values R.sub.0, G.sub.0, B.sub.0 ; (b) transforming the color locus F.sub.0 of the hue T.sub.0 to be recognized into the chrominance plane of the chrominance/luminance color space by a first transformation of its color values R.sub.0, G.sub.0, B.sub.0 into corresponding chrominance values x'.sub.0, y'.sub.0, the color locus F.sub.0 being transformed into a chrominance plane of the chrominance/luminance color space such that the transformed color locus F'.sub.0 lies on one of the axis segments of an X'Y' color coordinate system in the chrominance plane, and retaining transformation coefficients required therefor; (c) and during actual hue recognition scanning the color surface point-by-point and line-by-line for acquisition of measured color values R, G, B; (d) continuously transforming color loci F of the hues of the scanned colors into the chrominance plane by a second transformation, of the acquired measured color values R, G, B into corresponding chrominance values x',y', the color loci being transformed into the chrominance plane with the previously determined and retained transformation coefficients; (e) selecting those chrominance values x', y' whose corresponding transformed color loci F' lie in a same half of the X'Y' color coordinate system as the transformed color locus F'.sub.0 of the hue T.sub.0 to be recognized; (f) acquiring a hue signal T' by forming a quotient of absolute values of the selected chrominance values x',y', which respectively correspond to a tangent of an angle .beta. described by the corresponding axis segment and a connecting line between an origin of the color coordinate system and the transformed color locus F' of the hue of a scanned color, whereby the hue signal T' is a measure of the respective absolute value-wise deviation in hue of the hue of the scanned color from the hue to be recognized; and (g) acquiring a hue recognition signal E' by combining a substantially constant auxiliary control signal H with the hue signal T', said hue recognition signal E' having its highest values when scanning the hue T.sub.0 to be recognized and having the value zero when scanning a hue having a prescribed, maximum hue deviation tan .beta..sub.g, whereby a sector-shaped hue recognition region is defined with limits around the hue to be recognized.