What is the purpose of applying a primer before painting?

Applying a primer before painting serves several important functions, with the primary purpose being to increase adhesion and ensure better surface coverage. Primers are formulated to create a strong bond between the surface and the paint, which significantly enhances the durability and longevity of the finished paint job. This adhesion is crucial, especially on surfaces that may not otherwise bond well with paint, such as metal or plastic.

A primer can also help to seal porous surfaces, which prevents the paint from soaking in unevenly, leading to a more uniform finish. In doing so, it allows the topcoat to lay down more smoothly and consistently, improving overall appearance. Additionally, the primer acts as a barrier that can help to prevent issues such as peeling or chipping, further contributing to the durability of the paint layer applied afterward.

While other options address different aspects of painting, they do not reflect the primary function of a primer, which is centered around enhancing adhesion and ensuring an even application of the paint.