Haze
Haze refers to the scattering of light by a surface that causes a reduction in the contrast of a reflected image. It results in a milky appearance which can reducing the perceived depth of the finish.
The visibility of haze on a surface is influenced by viewing conditions and the background colour of the material.
Viewing conditions- Haze effects are highly visible when viewed with a high intensity specular light- for example viewed with a powerful inspection light or outside in bright sunshine.
Haze effects diminish the perceived quality of high gloss coatings and are usually an undesirable attribute.
Causes of Reflection Haze in a Surface
Surface Roughness and Texture
Microscopic Irregularities: Small-scale surface roughness and microscopic irregularities scatter light in various directions, causing a diffuse reflection. This scattering creates a hazy appearance around the main reflection.
Physical Texture: Surfaces with physical textures, such as fine scratches or uneven coatings, can scatter light and contribute to haze.
Contaminants and Impurities
Dust and Particles: Presence of dust, dirt, or other particles on the surface can scatter incident light, leading to haze.
Chemical Residues: Residues from cleaning agents, polishing compounds, or manufacturing processes can leave behind films or particles that scatter light.
Coating and Material Defects
Inhomogeneous Coatings: Variations in the thickness or composition of coatings can create regions that scatter light differently, increasing haze.
Material Inclusions: Embedded particles or inclusions within the material or coating can scatter light and contribute to a hazy reflection.
Subsurface Imperfections
Internal Scattering: Imperfections beneath the surface, such as air bubbles, voids, or subsurface cracks, can scatter light internally and cause haze.
Layer Interfaces: Interfaces between different layers of a coating or composite material can reflect and scatter light, contributing to haze.
Degradation and Wear
Aging and Weathering: Environmental exposure, UV light, and aging can degrade the surface quality, increasing roughness and promoting light scattering.
Mechanical Wear: Repeated mechanical actions, such as cleaning, polishing, or abrasion, can introduce surface defects that scatter light and increase haze.