ISO 5-4:2009规定了定义ISO 5标准反射密度的几何条件。它还建议可用于仪器设计的几何条件公差。ISO 5-3中规定了光谱条件。 ISO 5-4:2009还规定了极化（如果包括该特性）和背衬材料的要求，并就精度和线性提出了建议。 虽然主要用于测量摄影和图形艺术材料的反射特性，但ISO 5-4:2009也适用于测量其他材料的反射特性。

ISO 5-4:2009 specifies the geometric conditions for the definition of ISO 5 standard reflection density. It also recommends tolerances on geometric conditions that can be used in the design of instruments. The spectral conditions are specified in ISO 5-3. ISO 5-4:2009 also specifies the requirements for polarization (if that feature is included) and for backing material, and makes recommendations regarding accuracy and linearity. Although intended primarily for use in the measurement of the reflection characteristics of photographic and graphic arts materials, ISO 5-4:2009 is also applicable to the measurement of these characteristics for other materials.