What effect does light fastness have on paint?

Light fastness refers to the ability of a paint to resist fading or color changes when exposed to light, particularly sunlight. When a paint is described as having good light fastness, it means that it will retain its original color and brightness over time, even when subjected to prolonged exposure to light sources. This quality is essential for artworks that should maintain their aesthetic integrity throughout the years, especially if they are displayed in well-lit environments.

The other options do not accurately reflect the impact of light fastness. For example, light fastness does not relate to the reflectivity of the paint or its drying time, nor does it influence the odor of the paint. Thus, the correct answer clearly highlights the protective quality of light fastness in preserving the colors of paint against fading over time.