Whether you need to paint the whole surface depends mainly on what topcoat you are spraying. If it is a solid color paint, you can use the method of partial touch-up, that is, the whole surface can be painted. If it is metallic paint or pearlescent paint (which contains shiny particles), it is best to spray local complementary color paint and overall varnish. This painting process is to spray several layers of colored paint (painted with color) to cover the color of iron plate or putty, and then spray two layers of varnish (colorless and transparent, good gloss; It can play the role of wear resistance and aging resistance, and can protect the bottom color paint to complete the spraying work.
Metallic paint and pearlescent paint need local complementary color paint because color matching paint is very difficult and easy to produce color difference, which affects the appearance of the car body; It is an ideal painting method to make up the color paint and then spray varnish on the whole, which is not easy to see the color difference. In other words, it must be painted as a whole, as 4S stores often do.