Before starting our journey into texture mapping, it is important to understand how diffuse materials work. Certain objects might have a uniform color and smooth surface, but not smooth enough to shine on reflected light. These matte materials are best represented with a Diffuse shader. While in the real world, pure diffuse materials do not exist; Diffuse shaders are relatively cheap to implement and find a large application in games with low-poly aesthetics.
There are several ways in which you can create your own Diffuse shader. A quick way is to start with the Standard Shader in Unity 5 and edit it to remove any texture, similarly to what was previously done in Chapter 1, Creating Your First Shader.