The reflection model known as the ray method, is based on the assumption that incident light is specularly reflected
by the local tangent plane on the surface.
When the condensate appears, it steals light from the specularly reflected
beam, scattering it diffusely.
For textured (and hence rather rough) surfaces, the measured gloss contains specularly reflected
light as well as a significant contribution of the diffuse reflectance.
Gloss is defined as the optical property that measures the ratio between specularly reflected
intensity and the incident light intensity.
However, if the specularly reflected
beams are not picked up, it may be more difficult to achieve the same accuracy.