Suga Test Instruments Co., Ltd.

Kiyoshi Chaki

Shigeru Suga

Hiroshi Matsuki

Shigeo Suga

Takao Sumiyoshi

Etsuji Natori

Katsuaki Mitamura

A method of determining the color difference between two similar colors including the steps of determining the tristimulus values for a reference color with which another color is to be compared, providing a planar chromaticity diagram for the values other than brightness in which the values for the reference colors are at the origin and the abscissa and ordinates of the diagram, determining the hue of the reference color and plotting in said diagram an equi-hue line, determining the tristimulus values for the other color to be compared to the reference color and plotting the values other than brightness on the diagram, plotting an equi-saturation line on the diagram perpendicular to the equi-hue line and extending through the origin, plotting lines parallel to the equi-hue and equi-saturation lines through the position of the plotted values for the other color and extending across the equi-hue and equi-saturation lines, so that the difference in the tristimulus values for the other color from the reference color are shown by measurements along said parallel lines. In addition, a brightness line is provided having the brightness value of the reference color at the center of the line with values of greater brightness on one side of the center and values of less brightness on the other side of the center, and plotting the brightness of the other color on the line, whereby the difference in brightness for the other color from the reference color is shown by measurement along the line.

Color indication comparison method

A light fastness/weather resistance accelerated test apparatus, including a test tank having a discharge duct, a light source at the center of the test tank with a sample rotating frame rotatable around the light source and a black panel thermometer mounted on the sample rotating frame. A sensor on the sample rotating frame senses the temperature at the position of a sample. An air flow regulator is provided on the test tank, a blower is mounted for discharging air into the bottom of the tank, and a circulating duct is connected between the air flow regulator and the blower. A damper in the air flow regulator is movable to open the inside of the tank to the discharge duct or to direct air from within the tank into the circulating duct. An air mixer has a further damper and a bypass opening into the air flow regulator. The further damper is controlled to direct air through the bypass in response to the temperature outside the apparatus.

Light fastness/weather resistance accelerated test machine with an air

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Shinjuku, Japan

Kiyoshi Chaki