Detailed knowledge for detailersArticles related to correction
The colored coat is sometimes referred to as the base coat. This is a layer of paint that holds the color in which the panel is to be painted. This layer covers the primer and is usually finished with a layer of clear coat.
Headlights are often made from plastic, which can turn dull over time. Polishing will remove the matte layer and slowly reveal the clear and transparent finish again.
Plexiglass/perspex is a very soft type of plastic (Polymethyl methacrylate) that is very rarely used. Just like glass or paintwork, it can suffer from surface imperfections. Swirls and scratches can be very visible because it is fully transparent.
The refractive index is a way of measuring how lights behaves through a certain medium. This number gives an indication of how light reacts and how light is reflected. Manufacturers use (among other things) this as an indication of how light is reflected by a protective product and how that will make the surface look.