scope:

This method provides a measure of diffuse opacity (paper backing) of white and near-white papers, previously known as "printing opacity."

The method may be employed for colored papers on condition that their reflectance (paper backing) is greater than 20% and their diffuse opacity (paper backing) is greater than 45% (1).

The method is not suitable for highly transparent papers such as glassine.

This method employs d/0 geometry, illuminant C, and paper backing whereas TAPPI T 425 "Opacity of Paper" employs 15/d geometry, illuminant A, both 89% reflectance backing and paper backing.

This method is similar to ISO 2471.