1.1 这些试验方法确定并报告了粉末涂层相对于两个参数的遮盖力: 1.1.1 试验方法A——给定薄膜厚度下的对比度 1.1.2 试验方法B-0.98（98 %) 对比度。 注1: 测量的参数遵循粉末涂料行业的实践，通过测量与薄膜厚度相关的遮盖力，而不是测试方法中使用的“铺展率”函数 D344 和 D2805 以及其他隐藏能力测试方法。 注2: 隐藏能力在光度法上被定义为在0.98对比度下的扩展速率。参见术语中的扩展速率和隐藏能力的定义 D16 , D2805 ，以及 油漆和涂层测试手册 . 注3: 对比度0.98在涂料行业中通常被接受为代表反射计隐藏功率测量的“完全”隐藏。但在视觉上，以及在光度上，它都略不完整。 1.2 这些试验方法包括测定静电喷涂粉末涂料的遮盖力。 1.3 这些测试方法通过反射计和厚度计测量来确定隐藏能力。它们仅限于最小CIE-Y反射率为15的涂层 %. 1.4 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 1.5 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者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。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 在特定膜厚度下的对比度是用于生产控制和采购规范的有用的隐藏能力参数。 5.2 隐藏能力越大，每单位面积所需的涂层就越少，以获得足够的隐藏效果。因此，对于涂层成本和比较涂层价值而言，隐藏能力的知识是重要的。

1.1 These test methods determine and report the hiding power of a powder coating with respect to two parameters: 1.1.1 Test Method A—Contrast Ratio at a given film thickness 1.1.2 Test Method B—Film thickness at 0.98 (98 %) contrast ratio. Note 1: The measured parameters follow powder coating industry practice by measuring hiding power in relation to film thickness, rather than the “Spreading Rate” function employed in Test Methods D344 and D2805 and other hiding power test methods. Note 2: Hiding power is photometrically defined as the spreading rate at 0.98 contrast ratio. See definitions of spreading rate and hiding power in Terminology D16 , D2805 , and the Paint and Coatings Testing Manual . Note 3: The contrast ratio 0.98 is conventionally accepted in the coatings industry as representing “complete” hiding for reflectometric hiding power measurements. But visually, as well as photometrically, it is slightly less than complete. 1.2 These test methods cover the determination of the hiding power of powder coatings applied by electrostatic spraying. 1.3 These test methods determine hiding power by means of reflectometric and thickness gauge measurements. They are limited to coatings having a minimum CIE-Y reflectance of 15 %. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 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. 1.6 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 Contrast ratio at a specified film thickness is a useful hiding power parameter for production control and purchasing specifications. 5.2 The greater the hiding power, the less coating is required per unit area to obtain adequate hiding. Knowledge of hiding power is therefore important in regard to coating costs and for comparing coating value.