Abstract: A method giving a color tone-evaluating result which catches the deepness and transparency feelings of a coating film in an objective manner, and a device for use of this method. The evaluating results are obtained by projecting a luminous flux on a coating film, the high light saturation and/or high light excitation purity of the coating film are gotten on a basis of a high light part which is in an angle range of 5.degree. to 15.degree. against the regularly reflecting luminous flux in the reflecting light, and that, if necessary, the shade saturation and/or shade excitation purity are gotten on a basis of a shade part which is in an angle range exceeding 15.degree..

Abstract: The measurement of surface characteristics such as distinctness-of-image glossiness and/or surface roughness of a sample is carried out by projecting an image of a pattern, reflected from the surface of the sample, onto an image forming plane, transforming the spatial distribution of the intensity of light on the image forming plane according to Fourier series, and quantifying the distinctness-of-image glossiness or the surface roughness according to the light power strength at a particular spatial frequency.

Abstract: A measuring device for measuring the change in time-dependent thickness of the paint layer without any need of direct contact thereto. The device is provided with an optical arrangement which is well-known as Michelson-interferometer in principle, and is effective to obtain sharp and clear interference fringes even though the paint layer has a low reflectivity. It is also possible at laboratory side to observe the change of the paint layer under the circumstances to which the paint layer may be exposed actually.