Car touch-up painting can be done either in whole or partial sections depending on the situation. Whole-section painting: The reason for performing whole-section painting in car touch-ups is to prevent the painted area from peeling off. The repair scope needs to be determined for car touch-up painting: carefully inspect the damaged area. If the damage exceeds one-third of the component, a blending repair method should be adopted. Blending repair involves applying clear coat to the entire component while transitioning the base coat from the damaged area to the original paint, thus maximally preserving the original car paint and avoiding color mismatch issues. This is because when one-third of the area is damaged, processes like sanding, primer application, base coat, clear coat, and blending will cover over two-thirds of the component, leaving very little original area - making spot repair meaningless. Partial-section painting: For partial spraying, if the topcoat color can be adjusted very accurately, it would facilitate the repair. However, in practice, it's extremely difficult to perfectly match the touch-up paint color with the old paint color. Even with identical composition, color difference may still occur after spraying. To minimize color discrepancy between new and old paint, experienced automotive painters have accumulated extensive practical knowledge over years of practice to reduce color differences in partial touch-up painting to the minimum.
