What is a palette knife? A palette knife is one of many tools used for painting. It is usually a smaller tool, and looks kind of like a cake server. However, palette knifes are slimmer and are a more consistent shape. Palette knives were originally used for collecting, distributing and mixing oil paints; More recently, however, painters have been experimenting with the tools and using them for the application of the paint. The palette knife technique portrays a lot more emotion and takes a greater amount of skill to make dashes and wipes of paint, look like a recognisable and lifelike imagine / object.