Method for selecting an imaging rule for pixel-wise transformation of a three-channel color image of a recorded object into a grayscale image representing this object, - wherein a three-channel reference image of a reference object is selected and predetermined, - a brightness controller is provided to select a brightness value (m), - wherein a contrast controller is provided to select a contrast value (s) - wherein a color angle controller is provided to select two color angle values (θ,φ) - wherein a brightness value m, a contrast value s, and two color angle values θ and φ are selected, - wherein, starting from the two selected color angle values (θ, φ), provisional weighting factors (w r ', w g ', w b ') may be determined as follows: w r ′ = sinθ ⋅ cosφ, w g ′ = sinθ ⋅ sinφ, w b ′ = cosθ, - wherein an auxiliary transformation (T') is determined as follows: T'(r, g, b) = w,' - r + w g ' · g + w b ' · b, - wherein a grayscale image with the grayscale values (J[x.y]) given below is produced from the three-channel reference image with the three color values R r (x,y), R g (x,y), R b [x,y] at the respective coordinates (x, y) by pixel-wise application of the auxiliary transformation (T'): J x y = T ′ R r x y, R g x y, R b x y, - wherein the mean value M and the standard deviation S of the grayscale values (J[x,y]) of the auxiliary grayscale image are determined, - wherein weighting factors (w r, w g, w b) are determined as follows: w r = w r ′ ⋅ s / S, w g = w g ′ ⋅ s / S, w b = w b ′ ⋅ s / S, - wherein an offset value (d) is determined as follows: d = m − M, - and wherein the imaging rule is determined as follows: T r g b = w r ⋅ r + w g ⋅ g + w b ⋅ b + d. - wherein a three-channel reference image of a reference object is selected and predetermined, - a brightness controller is provided to select a brightness value (m), - wherein a contrast controller is provided to select a contrast value (s) - wherein a color angle controller is provided to select two color angle values (θ,φ) - wherein a brightness value m, a contrast value s, and two color angle values θ and φ are selected, - wherein, starting from the two selected color angle values (θ, φ), provisional weighting factors (w r ', w g ', w b ') may be determined as follows: w r ′ = sinθ ⋅ cosφ, w g ′ = sinθ ⋅ sinφ, w b ′ = cosθ, - wherein an auxiliary transformation (T') is determined as follows: T'(r, g, b) = w,' - r + w g ' · g + w b ' · b, T'(r, g, b) = w,' - r + w g ' · g + w b ' · b, - wherein a grayscale image with the grayscale values (J[x.y]) given below is produced from the three-channel reference image with the three color values R r (x,y), R g (x,y), R b [x,y] at the respective coordinates (x, y) by pixel-wise application of the auxiliary transformation (T'): J x y = T ′ R r x y, R g x y, R b x y, - wherein the mean value M and the standard deviation S of the grayscale values (J[x,y]) of the auxiliary grayscale image are determined, - wherein weighting factors (w r, w g, w b) are determined as follows: w r = w r ′ ⋅ s / S, w g = w g ′ ⋅ s / S, w b = w b ′ ⋅ s / S, - wherein an offset value (d) is determined as follows: d = m − M, - and wherein the imaging rule is determined as follows: T r g b = w r ⋅ r + w g ⋅ g + w b ⋅ b + d.