[Example of Allowance by Color / Color Story] NIPPON DENSHOKU INDUSTRIES CO.,LTD.

We have released the instruments with high accuracy which is useful for measuring the color and the light of materials. In this page, we introduce the basis of important information for measuring the color and the light including [preface of color story],[the three elements of color : hue - value - chroma], [munselll specification], [the recognition process of color], [the spectrum of light(spectrum distribution)], [the world of color for three-dimensional space of three stimulation value xyz], [what is ucs(uniform color space)], [example of color tolerance] and [unbalanced color judgement method]

When you transform three stimulus values XYZ into UCS(Uniform Color Space), it can be displayed at L*a*b* Color Specification System, Three-Dimentional Sphere (See Fig.10) and you can compare small and large of perceptual color difference in the distance of two colors coordinates.
In other words, the range of color allowance is expressed by color difference value.
Basically, the color allowance should be judged by agreement between the parties. For your reference, See Fig.11. In this figures, we introduce the case in common use at JIS regulation or in a variety of industries.

Color Tolerance	Color difference ΔE*	The extent of color difference	Standards
Avaluative level	0～0.2	The extent that Human can't discriminate. It is impossible to measure the color differences using the special adjusted measuring instruments.
The limit of discrimination	0.2～0.4	It is possible to measure the color differences in the range of 0.2 ～ 0.4, using the special adjusted measuring instruments. The people who was trained can distinguuish.	JIS L 0804 JIS L 0805
Grade AAA Color tolerance	0.4～0.8	This is the limit to set up the strict color difference standards with the decision of the human visual.	The particular strict standards stipulated between the persons concerned
Grade AA Color tolerance	0.8～1.6	People can tell the color differences, if samples are put side by side.	The standard of the Defense Agency. The standard of the National Police Agency. The standard of general ship inspection.
Grade A Color tolerance	1.6～3.2	In color comparison, this level is regarded as unrecognized and same color in general.	JIS Z 8721 JIS L 0809 The color tolerance of general color chips.
Grade B Color tolerance	3.2～6.5	Each colors of this range are regarded as the same colors. But the clients concerning paints and inks industry will make complaints about the color difference.	The allowable color difference in color management in general.
Grade C Color tolerance	6.5～13.0	This color tolerance corresponds to the color difference of JIS standard color chips.	JIS S 6006 JIS S 6007 JIS S 6016 JIS S 6020 JIS S 6028
Grade D Color tolerance	13.0～25.0	Each colors over ΔE 13 are not same color anymore.	JIS D 0202 JIS E 3701 JIS Z 8102 JIS Z 9101 JIS Z 9102 JIS Z 9107

[Fig.11 : Example of Allowance by Color]