5.1 Laboratory hiding power measurements of architectural coatings generally employ blade-type applicators that lay down films of highly uniform thickness. But practical applicators, such as rollers, pads, and brushes, typically apply films that lack uniformity due to incomplete leveling, resulting in the practical hiding power of most paints being less than that measured on films applied with a drawdown blade. This test method simulates practical application procedures and conditions so as to provide an indication of the actual hiding performance obtainable when a paint is applied by an experienced worker. It is not intended to duplicate painting as done by the average consumer.
5.2 Since the rheological characteristics of a paint and its interaction with the applicator are influencing factors, rank order correlation between this test and one done by drawdown might not be obtained.
1.1 This test method measures the ability of a paint to hide or obscure a surface to which it has been applied by a practical application procedure. This test method covers the use of a paint roller, but the concept is expected to work equally well when the application tool is a paint brush or paint pad.