Painting scale models is common practice for modelers of all skill levels. The goal is to reproduce the historical color scheme and markings to individualize and increase the realism of the model. Many painting techniques have evolved to serve scale modelers. These techniques use near limitless application processes, varying the consistency, type of paint, and application method. Three main tools are used to apply paint: brushes, spray cans, and airbrushes. Brushes are favored for detail work and general paintwork. Spray paints are used to base coat models or dioramas. Airbrushes are used in a multitude of rolls, filling the niche taken by the spray can as well as giving the modeler the ability to lay down easier soft-edged lines and highlights. Types of paint used are also varied. some modelers prefer acrylic paint, while other prefer enamel paint, and yet more prefer oil paint. However, most hobbyists use a combination of 2, or all three to paint their models. The process of painting a model commonly begins with a primer to help paint adhere to the surface of a model. From there, base colors are applied in either a monotone or a camouflage scheme, depending on the subject. Depth is than added using highlights, shadows, and washes (thinned paint that acts on capillary action). Vehicle markings, including numbers and roundels, are often reproduced with waterslide decals.