Hiding power

Hiding power - the ability of a pigment or pigmented coating material to evenly apply the color of the surface on which it was applied, or if applied to a black and white surface, reduce the contrast between black and white parts of the surface until the difference in lightness between them completely disappears.

According to Russian standards, hiding power is expressed in grams of pigmented material needed to cover 1 m² of surface. In Europe, as a rule, hiding power is expressed in m² / l.

Hiding power is determined both visually and by an instrumental method - by determining the reflection coefficient or color coordinate Y using a color measuring device ( spectrophotometer ). When visually determining the hiding power, paint and varnish materials are applied evenly on thin transparent, colorless glass plates applied to opaque substrates. Typically, the substrate has the appearance of a checkerboard. Application of the material is carried out until the boundaries between the black and white portions of the substrate disappear.

For instrumental determinations, black and white substrates are used or the material is applied to black and white paper using an applicator .

A surface is considered covered if the contrast coefficient , i.e. the ratio of the reflection coefficient of the coating over the black substrate to the reflection coefficient over the white substrate, exceeds 0.98. ^[one]