Texture Baking - Blender Master Class: A Hands-on Guide to Modeling, Sculpting, Materials, and Rendering - page 145

Figure 10-7: Baking a normal map. Normal Space is set to Tangent, and the normals are baked from the sculpted mesh to our
final model—this time without subdivision. Some artifacts are present in the bake, but these can be corrected later in GIMP
(see Chapter 11).
Figure 10-8: The normal map applied as part of the
material, previewed in the 3D Viewport using GLSL
shading. The artifacts from the bake can be seen
on the wing as black areas, but this can be fixed
later in GIMP simply by painting over them.