Diffuse map provides a pattern of colors for a material.
You can select an image file as a texture map or a procedural map to assign a pattern or texture to a material’s diffuse color. The colors of the map replace, or partially replace, the material’s diffuse color component in the Material Editor. This is the most common kind of mapping.
Mapping the diffuse color is like painting an image on the surface of the object. For example, if you want a wall to be made out of brick, you can choose an image file with a photograph of bricks, or you can use the procedural tiles map to simulate a brick pattern.
