Instrumental Evaluation：

仪器评级：

The principle of instrument rating is to use the absolute reflectance of a known standard whiteboard for calibration. Measure the spectral power distribution of the sample reflection or its own reflectance characteristics. Then, based on the spectral measurement data, calculate the tristimulus values, chromaticity coordinates, and CIELAB uniform color space of the object under standard illumination. Convert the grey scale of color change and staining fastness through a series of formulas.

仪器评级其原理为利用已知标准白板的绝对反射率来定标，测定样品反射的光谱功率分布或其本身的反射光度特性，然后根据光谱测量数据计算出物体在标准照明体下的三刺激值、色度坐标、CIELAB均匀颜色空间等，并通过一系列公式转换成变色和沾色牢度的灰卡级数。

Sometimes when reading a report, you may have questions. Why is the test result for color fastness to soap washing and discoloration displayed on the test report at level 3? Is the standard requirement ≥ 3-4, or is it judged as unqualified? Is the report misjudged?

有时候看报告时会产生疑问，为什么检测报告上显示的耐皂洗色牢度变色的测试结果是3级，标准要求是≥3-4，还是判定不合格？是否报告判定错了？

In fact, the result judgment is correct. The level 3-4 of color fastness evaluation is not a general mathematical concept interval, it is a level that represents the test result between level 3 and level 4.

其实结果判定是对的。色牢度评定的级数3-4级不是一般数学概念上的区间，它是一个级数，是表示测试的结果处于3级与4级之间。