1.1 本试验方法描述了用仪器测定反光膜夜间反光色度坐标的方法。 1.2 该方法包括基于三刺激滤波器色度计的程序和基于光谱测量的程序。 1.3 该方法描述了一组测试几何形状（使用0.33°观察角和5°入射角）和孔径。 1.4 所得色度坐标用于利用CIE光源A的CIE 1931色度系统。 1.5 如果需要对其他照明源、几何形状或其他材料进行测量和计算，请参考实践中描述的一般做法 E811 . 1.6 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.7 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本试验方法的结果用于评估反光膜是否符合行业标准和政府法规（如规范）的夜间颜色要求 D4956 和美国联邦法规第23编第655部分F子部分。 5.2 本试验方法规范中的要求是针对夜间观察的材料色度。这些要求通常使用四个或五个角点表示，这些角点形成一个限制可接受色度范围的方框。这些规范中的大多数本质上是分类的；它们描述了可从颜色命名或编码目的识别的小范围颜色 5.3 符合规范的方法是绘制测量值( x、 y )并确定测量点是否在感兴趣颜色的规格框内。

1.1 This test method describes the instrumental determination of the nighttime retroreflected chromaticity coordinates of retroreflective sheeting. 1.2 This method includes a procedure based on tristimulus filter colorimetery and a procedure based on spectral measurements. 1.3 A single set of test geometries (using 0.33° observation angle and 5° entrance angle) and apertures are described in this method. 1.4 The resulting chromaticity coordinates are for use with the CIE 1931 chromaticity system utilizing CIE Illuminant A. 1.5 If measurements and calculations are required for other sources of illumination, or geometries, or other materials, the user is referred to the general practice described in Practice E811 . 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 The results of this test method are used to assess conformance of retroreflective sheeting to the nighttime color requirements of industry standards and government regulations, such as Specification D4956 and U.S. Code of Federal Regulations Title 23 Part 655 Subpart F. 5.2 Requirements in specifications referring to this test method are for the chromaticity of the material as viewed at night. These requirements are generally stated using four or five corner points that form a box that limits the range of acceptable chromaticity. Most of these specifications are categorical in nature; they describe a small range of colors that are recognizable from a color naming or coding purpose 5.3 The method for compliance with the specification is to plot the measured ( x, y ) values and determine if the measured point falls within the specification box for the color of interest.