What does good holdout refer to in painting?

Good holdout refers to the quality of a topcoat to retain its gloss and to optimize the appearance of the finish by not sinking into surface imperfections. When a topcoat has good holdout, it means that it maintains its smoothness and does not compromise its glossy finish, even when applied over a primer or previous coatings that might have varying textures. This characteristic is crucial for achieving a uniform and visually appealing finish on painted surfaces. The ability to avoid shrinkage into imperfections ensures that the final appearance is consistent and reflective, contributing to the overall aesthetics of the painted job.

In the context of the other options, the drying speed of a primer does not relate directly to holdout and more to curing processes, while adhesion pertains to how well a primer bonds to surfaces rather than the glossy quality of a topcoat. Compatibility speaks to how different paint types work together, which is also unrelated to the concept of holdout in terms of gloss retention and surface quality.