Manual/Lighting
From BlenderWiki
Introduction
Lighting is a very important topic in rendering, standing equal to modeling, materials and textures. The most accurately modeled and textured scene will yield poor results without a proper lighting scheme, while a simple model can become very realistic if skilfully lit. Lighting, sadly, is often overlooked by the inexperienced artist who commonly believes that, since real world scenes are often lit by a single light (a lamp, the sun, etc.) a single light will also do in computer graphics. This is false because in the real world even if a single light source is present, the light shed by such a source bounces off objects and is re-irradiated all over the scene making shadows soft and shadowed regions not pitch black, but partially lit.
The physics of light bouncing is simulated by Ambient Occlusion (a world setting), buffer shadows (which approximate shadows being cast by objects), ray tracing (which traces the path of photons from a light source). Also, within Blender you can use the Radiosity engine. Ray tracing, ambient occlusion, and radiosity are slow processes. Blender can perform much faster rendering with its internal scan line renderer, which is a very good scan line renderer indeed. This kind of rendering engine is much faster since it does not try to simulate the real behavior of light, assuming many simplifying hypotheses.
In this User Manual we have placed Lighting before Materials; you should set up your lighting before assigning materials to your meshes. Since the material shaders react to light, without proper lighting, the material shaders will not look right, and you will end up fighting the shader, when it is really the bad lighting that is causing you grief. All of the example images in this section do not use any material setting at all to the ball, cube or background.
In this chapter we will analyze the different type of lights in Blender and their behavior, we will analyze their strong and weak points. We also describe many lighting scheme, including the ever-popular three point light method.
If you have started down the road of assigning materials, and are just now fiddling with the lighting, we suggest that you create a default, generic grey material; no VCol, no TexFace, no Shadeless, just plain old middle grey with an RGB of (0.8,0.8,0.8). If you click the auto-namer button, it should fill in "Grey". In the RenderLayer tab, enter "Grey" into the Mat: field. If the name sticks, you know you entered is correctly. This will override any materials you may have set, and render everything with this flat boring color. Using this material, you can now go about adjusting the lighting.
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