ISO 5-2:2009规定了测量ISO 5标准漫反射和投影透射密度的几何条件。 ISO 5标准漫反射密度主要适用于在透明照明器或观察盒上观看、接触打印或使用漫反射照明系统投影的摄影图像的测量。 ISO 5标准投影密度主要适用于使用光学冷凝器系统投影的摄影图像的测量。 虽然主要用于测量摄影图像，但ISO 5-2:2009中规定的密度测量方法通常适用于滤光片和其他透明材料。

ISO 5-2:2009 specifies the geometric conditions for measuring ISO 5 standard diffuse and ？/4,5 and ？/1,6 projection transmittance densities. ISO 5 standard diffuse density is primarily applicable to measurements of photographic images to be viewed on a transparency illuminator, or viewing box, to be contact printed, or to be projected with a system employing diffuse illumination. ISO 5 standard projection density is primarily applicable to measurements of photographic images to be projected with systems employing optical condensers. Although primarily intended for the measurement of photographic images, the densitometric methods specified in ISO 5-2:2009 are often applied to optical filters and other transparent materials.