The measured result of the relative spectral sensitivity of some detectors by two tandem monochromators method are described with the discussions of the error in the measurement. The Contents of the present paper are summarized as follows:
(1) The polarization characteristics of the standard lamp are experimentally assured nearly unpolarized in the spectral range of 260-800 nm.
(2) The error caused by the finite slit width are calculated for the measured relative spectral sensitivity of some detectors. The error with the spectral sensitivity of the type S-11 is estimated more than 1.0% in the wavelength region longer than 600 nm and that of the type S-20 less than 0.3% in the almost whole wavelength region involved.
(3) The measured relative spectral sensitivity of a detector by the present method are compared with that by the thermopile method. The deviation between them are found less than 2.2% in the visible range and 5.4 % in the wavelength region longer than 750 nm.

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As standard specimens of the specular reflectance, the authors have prepared some mirrors by vacuum deposition of aluminum and measured their specular spectral reflectance in the 0.4-14 μ m wavelength region. The aluminum thin film was deposited on optical flats having 30 mm diameter and 12 mm thickness by evaporation of 99.9% aluminum in a vacuum of 10^-5 Torr. The reflectance was measured with an instrument having Bennett and Koehler type optics. The precision of the measurement was ± 0.3% in the visible and far infrared regions but in the near infrared of about 0.9 μ m it was ± 0.6%. The result showed similar spectral reflectance to the data which were published on the aluminum films deposited in the same order of vacuum.

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We found that some SCRs, could turn off the anode current by a reverse gate trigger, like a GTO thyristor, on a small current level. With this kind of SCR, we developed a starter for fluorescent lamp (FL-40 S).
All starter actions viz. preheating the lamp electrodes, turning off the choke current for striking pulse voltage and keeping the starter inactive during lamp operation, are performed by the gate controls of the SCR. Moreover the control of the gate trigger suppresses the occurrence of abnormal burning of rectificated discharge.

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This paper is concerned with the design and the electrical characteristics of the leakage auto-transformer type constant wattage ballasts for the high pressure mercury lamps.
At first investigation, the necessary electric circuit constants for designing, such as, turns ratio, required leakage reactances, magnetizing currents, are derived from the equivalent circuit for the leakage auto-transformers by the use of the equivalent sine-wave analysis. And then, the circuit constants and electrical characteristics of the ballasts are calculated in a particular specification with the aid of the computer, and the quantitative relations between those constants are discussed.

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The heart rates, based on the R-R intervals, and pneumogramms of 18 subjects have been measured for 35 min. at illumination levels from 10 to 2, 000 lx. Light sources used were the fluorescent lamps with the color temperature of 4200 K. The wall in the test room was yellow-green close to 7.5 GY 8/2, and the room temperature was kept at 24 ± 1 ° C. The amount of physiological load was assessed from the mean heart rate, heart rate variability, and mean amplitude and period of pneumogramm.
At the same time, psychological effects were investigated by use of a simple questionnaire.
The results indicated that physiological load was minimum at the illumination level of 320 lx, and increased with increase or decrease in illumination level from 320 lx. Therefore the level of 320 lx appears to be the physiologically optimum level of illumination.
Psychologically, however, the level of 1, 000 lx was estimated to be the most desirable level of illumination, and desirability decreased as the illumination level was icreased or decreased from 1, 000 lx.

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The authors, who have made public four papers on the shadow characteristics under conditions that a light source and a shadow caster have geometrical shapes, deal with in this paper a research on some characteristics of a shadow produced by a horizontal disk as a shadow caster, which is set under a square light source.
First, three methods for numerical calculation of the illuminance within the shadow are explained briefly and discussed. They are (1) by the equations which are used in the illuminance calculation, (2) by the solid angle projection area and (3) by the computer program CONFAC II.
Secondly, the shadow characteristics under the following conditions are described.
(1) Varied positions of a horizontal square light source with the position of a horizontal disk fixed, and vice versa.
(2) Varied positions of a vertical square light source with the position of a disk fixed, and vice versa.
Finally, those results obtained are compared.

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As is well known, the high frequency (RF) breakdown voltage is independent of the cathode material (r) provided that the electron trapping condition is satisfied. Appling this principle to the discharge lamp, the complex of the phenomena in a lamp are separated into two parts, gas and electrodes. The frequency condition of the electron-trap for the actual HID lamps was found to be more than few MHz.
This RF breakdown method was applied to the diagnostics of the actual high pressure Hg lamps, high pressure Na lamps and metal halide lamps. The quantity of impurity in Hg lamps of high starting voltages could be estimated, without breaking the lamps. The behavior or the quantity of the impurity which had absorbed in the electrodes or the metal halides was also evaluated.
Thus, RF breakdown method for the diagnostics of the discharge lamps was found to be useful.

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Some specific properties of polarization are found in the grating-type monochromators which are generally used in the colorimetry of fluorescent samples. The present paper describes the errors in their spectrophotometry andcolorimetry caused by the presence of polarization properties in the measuring system. The results reported are as follows.
(1) A method is suggested in order to predict the reflected and the fluorescent spectral radiance factor which are expected to be measured by use of a measuring system with polarization properties. A method is further givenwhich estimates the spectrophotometric errors in the predicted radiance factors.
(2) The properties of polarization are described on the measuring system of two-monochromator method, the whitestandard surface, and the fluorescent samples used in the present study.
(3) Spectrophotometric errors in the reflected and the fluorescent radiance factor are estimated to the twokinds of fluorescent samples by use of the methods given in (1) and of the measured characteristics of polarizationin (2) necessary in the computation. In the two-monochromator method used, the error of the reflected spectral radiance factor is estimated not to be less than 19 at some wavelengths. However, the error of the fluorescent spectral radiance factor is relatively small and is estimated to be less than 0.006%.
(4) Colorimetric errors of fluorescent samples due to polarization are estimated in the cases of one-and two-monochromator method. The errors are given by the color difference in the CIE LAB unit, which are estimated to be less than 1.0 units and found to be negligibly small.

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This paper treats luminous color control methods in pulsed arc discharges of Ne-Hg lamps. Luminous color is widely controlled from red color of Ne to blue color of Hg by changing the waveform of discharge current. Synthesized waveforms are favorable to make the glow to arc transition sure and to get good performance of color change of the high luminance positive column.

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