[in Japanese]

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Although the spectral reflection curves of white diffusing paints used for inner coating of a photometric sphere are desired to be flat in visible region, the curves are markedly influenced by thicknesses of the coating layers. The color inside the illuminated sphere changes from a bluish cast through white to ivory as the thickness increased. Therefore, there must be the most suitable thickness for each paint.
For smoked MgO coating and other white coatings in the sphere, the auther measured the spectral reflecting distributions of them relating to their coating thicknessed and aiscussed the color temperature changes of the light from the photometric sphere.

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Hardy's and Perkin-Elmer's automatic recording spectrophotometers seem to be excellent with respect to photometric system and automatic recording mechanism. They adopt the so-called double beam type of optical system and the automatic recorder of comparison-and-balancing method.
Generally, for an automatic recorder of a measuring instrument, the balancing type is better than the deflection type in their abilities.
than the deflection type in their abilities. Recently, several types of automatic recording spectro-radiometer have been developed to meet the increasing demand, but most of them are of the deflection type, and we are aware of no one which adopts the flickering-and-balancing method. The task of a spectro-radiometer is not the same as that of a spectro-photonieter, so we cannot use the above method without some proper modifications. In spectro-radiometry for the measurement of spectral energy distributions of lights from a. c. operated fluorescent lamps, we have to deal with fluctuating lights. In this case, it is very important to select the frequency of flickering device, because the accuracy of measurements and the recording speed depend directly upon this choice: there are cases in which it is impossible to detect the signal expected in the resultant out-put voltage, or it is very difficult to design the electric circuits so as to have the apparatus operate satisfactorily.
In the first part of this paper, the time-varying functions of both fluctuating lights and the flickering process are introduced, and then the signal contained in the above waves is analyzed.
Next, the conditions to match the photometric and electric balance are discussed.
Finally, the procedure of selecting an optimum flicker frequency, necessary to attain the measurement accurately for an estimated fluctuating light, is proposed, and furthermore the necessary condition of electrical characteristics of the detection circuit is noticed.

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