A system - with a distal server displaying a virtual colour image in the form of an image file comprising individual colour values on its website, and - with a proximal computer connected to the server and comprising a display unit, said computer displaying the virtual colour image of the server on its display unit by means of an application program, characterized by [a] a reference card provided on the part of the computer and containing multiple differently coloured translucent reference areas (T1, T2, T3) besides a transparent or translucent area or an opening, [b.1] wherein a routine on the server and/or on the computer is then startable by the application program, said routine firstly outputting a first colour shade, for example cyan, with a first of the colour values, wherein said first colour shade is complementary to the colour, for example red, of one of the translucent reference areas (T1, T2, T3) of the reference card, [b.2] wherein the reference card is then holdable with that translucent reference area the colour of which is complementary to the first colour shade displayed on the display unit in front of said first colour shade, and a marking of that of the translucent reference areas (T1, T2, T3) for which the grey shade resulting from colour mixing of the first colour shade and the translucent reference area comes closest to a grey shade displayed on the display unit and falling through the area or the opening is determinable and storable, [c] wherein the step [b.1] and the step [b.2] are repeatable at least once to output a second colour shade, for example magenta, of a second of the colour values, said second colour shade being complementary to the colour, for example green, of another of the translucent reference areas (T1, T2, T3) of the reference card, and to determine and store the marking of said other of the translucent reference areas (T1, T2, T3), [d] wherein the markings of the reference areas (T1, T2, T3) determined in the preceding steps [b.1], [b.2], [c] and stored on the server and/or on the computer are inputtable in this order into a colour correction program started on the server and/or on the computer, and [e] wherein for every image file sent by the server the virtual colour image is adjustable by means of the colour correction program for each colour value contained in the image file by applying the markings used as correction values, and thus said virtual colour image is displayable in colours optimized in respect of its recording conditions. - with a distal server displaying a virtual colour image in the form of an image file comprising individual colour values on its website, and - with a proximal computer connected to the server and comprising a display unit, said computer displaying the virtual colour image of the server on its display unit by means of an application program, [a] a reference card provided on the part of the computer and containing multiple differently coloured translucent reference areas (T1, T2, T3) besides a transparent or translucent area or an opening, [b.1] wherein a routine on the server and/or on the computer is then startable by the application program, said routine firstly outputting a first colour shade, for example cyan, with a first of the colour values, wherein said first colour shade is complementary to the colour, for example red, of one of the translucent reference areas (T1, T2, T3) of the reference card, [b.2] wherein the reference card is then holdable with that translucent reference area the colour of which is complementary to the first colour shade displayed on the display unit in front of said first colour shade, and a marking of that of the translucent reference areas (T1, T2, T3) for which the grey shade resulting from colour mixing of the first colour shade and the translucent reference area comes closest to a grey shade displayed on the display unit and falling through the area or the opening is determinable and storable, [c] wherein the step [b.1] and the step [b.2] are repeatable at least once to output a second colour shade, for example magenta, of a second of the colour values, said second colour shade being complementary to the colour, for example green, of another of the translucent reference areas (T1, T2, T3) of the reference card, and to determine and store the marking of said other of the translucent reference areas (T1, T2, T3), [d] wherein the markings of the reference areas (T1, T2, T3) determined in the preceding steps [b.1], [b.2], [c] and stored on the server and/or on the computer are inputtable in this order into a colour correction program started on the server and/or on the computer, and [e] wherein for every image file sent by the server the virtual colour image is adjustable by means of the colour correction program for each colour value contained in the image file by applying the markings used as correction values, and thus said virtual colour image is displayable in colours optimized in respect of its recording conditions.