Three direction measurements for characterization of a surface containing metallic particles
AssigneeE. I. Du Pont de Nemours and Company
InventorDavid H. Alman
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Abstract
An improved method for instrumentally characterizing the optical properties of a surface containing metallic particles such as a paint containing metallic flakes by using multiangular spectrophotometric or colormetric measurements to derive color constants for the paint, wherein the improvement comprises using three multiangular measurements, preferably 15.degree., 45.degree. and 110.degree. as measured from the specular angle.
Claims3
An improved method for instrumentally characterizing the optical properties of a paint film containing metallic flakes by using multiangular spectrophotometric measurements to derive color constants for the paint, wherein the improvement comprises using three multiangular measurements utilizing the techniques of Detector Modulated Reflectance, taken at angles of about 15.degree., 45.degree., and 110.degree., as measured from the specular angle with an illumination angle of 45.degree. relative to the metallic paint film being optically characterized and determining X, Y and Z tristimulus values of a paint film by using the following equations:
- ##EQU2## wherein R is the reflectance factor data,
- x y z0 data on the sensitivity of the human eye,
- E is the irradiance of a light source and
- .lambda. function of wavelength in the visible light spectrum from 360-830 nanometers.
Dependencies are inferred from the claim text.