A chromatically non-uniform illumination device comprising: - an artificial broad-band light source comprising a white light source or a light source with a spectral bandwidth greater than 100 nanometers in the range of wavelengths between 400 nanometers and 700 nanometers, the artificial light source comprising a plurality of active elements, which emit photons or which absorb photons an re-emit them at a higher wavelength, and a plurality of lenses, each lens being optically coupled to a corresponding active element; - a chromatic diffuser located downstream the artificial light source, so that the lenses are interposed between the active elements and the chromatic diffuser; wherein the chromatic diffuser is configured to not emit light and to change the propagation direction of the light emitted by the artificial light source; and wherein the chromatic diffuser comprises elements of a first non-liquid material transparent to light in the range of wavelengths between 400 nanometers and 700 nanometers and having refractive index n 1, the elements of the first non-liquid material being dispersed in a second non-liquid material transparent to light in the range of wavelengths between 400 nanometers and 700 nanometers and having refractive index n 2, wherein a typical linear dimension d of the dispersed elements of the first non-liquid material satisfies the condition 5nm<d<300nm; and wherein a maximum dimension L max of the chromatic diffuser is equal to or greater than five times the minimum dimension d min of a projection of the largest of said active elements in a first plane perpendicular to a first direction, wherein: - in case the artificial light source is anisotropic, said first direction is the maximum emission direction (I max) of said artificial light source; otherwise - in case the artificial light source is isotropic, said first direction is defined by a straight line (I prox) that joins the two closest points of said artificial light source and chromatic diffuser; and wherein said maximum dimension L max of said chromatic diffuser is defined as the greatest between: - a transverse dimension defined as the maximum distance between couples of points belonging to a projection of the chromatic diffuser on the first plane; and - a longitudinal dimension, defined as the maximum distance between couples of points belonging to a projection of the chromatic diffuser on a second plane parallel to the first direction; the chromatic diffuser being thereby configured to separate blue radiation, scattered by the chromatic diffuser, from yellow radiation, transmitted by the chromatic diffuser. - an artificial broad-band light source comprising a white light source or a light source with a spectral bandwidth greater than 100 nanometers in the range of wavelengths between 400 nanometers and 700 nanometers, the artificial light source comprising a plurality of active elements, which emit photons or which absorb photons an re-emit them at a higher wavelength, and a plurality of lenses, each lens being optically coupled to a corresponding active element; - a chromatic diffuser located downstream the artificial light source, so that the lenses are interposed between the active elements and the chromatic diffuser; - in case the artificial light source is anisotropic, said first direction is the maximum emission direction (I max) of said artificial light source; otherwise - in case the artificial light source is isotropic, said first direction is defined by a straight line (I prox) that joins the two closest points of said artificial light source and chromatic diffuser; - a transverse dimension defined as the maximum distance between couples of points belonging to a projection of the chromatic diffuser on the first plane; and - a longitudinal dimension, defined as the maximum distance between couples of points belonging to a projection of the chromatic diffuser on a second plane parallel to the first direction;