| 摘要 |
PROBLEM TO BE SOLVED: To easily and correctly estimate radiant intensity and spectral radiant intensity of a reflector from a small number of measurement values when reflectivity and spectral reflectivity of the reflector is known. SOLUTION: When radiant intensity (lightness) of photographic paper 1 of a monochrome silver salt photo whose reflectivity Ci by an observation optic system of 0 deg. incidence and 45 deg. observation is known is to be predicted, first, achromatic photographic paper 2 of a silver photo similar to the photographic paper 1 of interest with high lightness whose reflectivity (a) by the observation optic system of 0 deg. incidence and 45 deg. observation 1 is placed on a position for observing the photographic paper 1 of interest and illuminated by a predetermined light source 11 for illuminating the photographic paper 1 of interest. Radiant intensity of the illuminated photographic paper 2 is measured by a radiant intensity meter 12 placed at an observation point for observing the photographic paper 1 of interest. Next, a measurement value (b) of the radiant intensity is divided by the reflectivity (a) to predict illumination intensity by the light source 11. Then the predicted value b/a of the illumination intensity is multiplied by the reflectivity Ci of the photographic paper 1 of interest to predict radiant intensity from the photographic paper 1. Where the prediction value of the radiant intensity is di, di=(b/a)Ci. |
