1.1 This test method covers the determination of the opacity of paper.

1.2 Two different types of "white" backing are specified, leading to two different opacity values, in accordance with Section 3.

1.3 This test method employs 15° diffuse geometry, Illuminant A/2° and 89% reflectance backing or paper backing. For the measurement of opacity with d/0° geometry, Illuminant C/2° and paper backing (see TAPPI T 519).

1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.