Transparency in the dried paint film allows characteristics from the substrate or undercoat to be visible.
While paints are designed for opacity, poor hiding can allow variances in the substrate or previously applied coating material to be visible through the dried paint film.
There are several reasons why a coating may appear transparent, or suffers from poor hiding levels. They are:
- Excessive use of reducer: Because reducers are totally transparent, using too much reducer takes away from the normal hiding level of the paint.
- Improper choice in undercoat material: Certain color primers are more difficult to cover, depending on the color of the paint. For instance, dark paint colors (such as black) will cover a dark undercoat faster than a light gray or white, just as a white paint will cover a light colored primer faster than a black or dark gray.
- Uneven color on substrate: Body fillers and other variations in substrate color may not be immediately visible beneath the paint film, though they can still have an effect on hiding, causing an uneven appearance.
- Insufficient material applied: Depending on the paint color used, sometimes a manufacturer’s suggestion is not enough to achieve proper hiding, and additional coats should be applied.
- Improper material preparation: Paint should be sufficiently agitated prior to use. This is especially true with older materials, because pigments may easily settle to the bottom of a container if left untouched for long periods.
Note: Certain colors and types of paint provide lower hiding levels than others, requiring additional coats to achieve desired appearance.
Continue applying properly agitated and reduced material until desired hiding level is achieved.