Which of the following is NOT classified as a type of paint?

Gel is not classified as a type of paint in the traditional sense but rather as a medium or additive used in painting. While watercolors, acrylics, and tempera are all recognized types of paint characterized by their composition and the methods used to apply them, gel typically refers to a thick, transparent substance that can modify the flow and consistency of paints, particularly acrylics. It can be added to paint to achieve specific textures or finishes, rather than standing alone as a paint type. Understanding the difference between actual paint types and mediums is essential for art education, as it helps in selecting appropriate materials for various artistic techniques and projects.