Final answer:
The purpose of powder after foundation is to set the foundation, absorb excess oil and moisture, reduce shine through diffuse reflection, and improve the longevity of makeup.
Step-by-step explanation:
The purpose of applying powder after foundation is multifaceted. One of the main benefits of using powder is that it helps to set the foundation, providing a smooth base for other makeup. Additionally, powder can help to absorb excess oil and moisture on the skin, which contributes to reducing shine due to its composition of small particles that lead to diffuse reflection. This is especially beneficial for those with oily skin types.
Moreover, powder improves the overall longevity of the makeup, helping it to stay in place throughout the day. The ingredients in powder such as mica, talc, or kaolin clay not only give cosmetics like eye shadow their texture and bulk but also fulfill functional purposes. For instance, mica absorbs moisture and adds shine and luster to makeup, while making it opaque. The use of various powders, including iron oxides and clays, also contributes to the pigmentation of products like eye shadows.