What is the primary function of Sun Protection Factor (SPF) in tanning?

The primary function of Sun Protection Factor (SPF) is to protect the skin from UV damage. SPF is a measure of how well a sunscreen can protect the skin from ultraviolet (UV) rays, which are responsible for sunburn and can lead to more serious skin issues such as premature aging and skin cancer. Specifically, SPF indicates the level of UVB protection provided; UVB rays are primarily responsible for causing sunburn. For example, if a product has an SPF of 30, it means that it takes 30 times longer for the skin to redden than it would without the sunscreen. This protective capability is crucial for maintaining skin health and preventing long-term damage from sun exposure.

In contrast, the other options suggest various effects that are not related to the primary role of SPF. Enhancing the tanning effect or accelerating skin darkening does not address the protective aspect against UV damage. Additionally, no product can remove sunburns, underscoring that the primary concern of SPF is preventive rather than restorative. Therefore, emphasizing the protective function of SPF is essential for safe tanning practices.