Using Normal maps to detail surfaces
Normal maps are special texture maps used to simulate surface details and bumps. Their purpose is to increase the level of apparent detail on a texture or object without adding any new geometry. Normal maps, as with other texture maps, can also be applied through Image Texture nodes, but they will require us to change a few extra things to let Blender know that this is a special type of image. Figure 4.11 shows an example of a Normal map.

Figure 4.11 – A simple Normal map
To apply this Normal map, we must first set Color Space to Non-Color in the Image Texture node. Then, we must add a normal map node and plug it into the Normal input of the Principled BSDF node. Blender will now know how to read this image correctly.

Figure 4.12 – Processing a Normal map
If we apply this Normal map to a material, it will simulate bumps on the surface, as shown in Figure 4.13.