How is surface finish measured?

Surface finish is primarily measured using a roughness profile, which assesses the texture and smoothness of a surface. This measurement is typically expressed in terms of parameters such as Ra (arithmetic average roughness), Rz (average maximum height of the profile), and others depending on the specific requirements of a given application.

While calipers and micrometers are tools used for various types of measurements, they are not specifically designed to quantify surface finish. Instead, these tools are better suited for dimensions and tolerances such as length and diameter, rather than the intricate details of surface texture. Therefore, the mention of none of the provided methods being correct aligns with the fact that only a roughness profile measurement can effectively evaluate surface finish.