What is the primary purpose of a base coat in nail application?

The primary purpose of a base coat in nail application is to protect the natural nail from staining. Base coats serve as a barrier between the natural nail and the nail polish applied on top. Certain pigments and chemicals found in colored polishes can cause discoloration or yellowing of the nail surface, especially with darker shades. By applying a base coat, it helps maintain the health and appearance of the natural nails by preventing these potential stains.

While other functions are important, such as adding shine or enhancing color, these are secondary to the core protective function of the base coat. Therefore, using a base coat is essential for maintaining the integrity of the nails, especially for clients who frequently use pigmented nail polishes.