Lights and Lighting
Lighting a map is both an art and a science. For Quake III Arena, the id designers worked to create instances of dramatic lighting, while attempting to maintain a relatively consistent intensity of light throughout the maps. Other designers worked to create dark realms, full of shadows in which lurking assassins could hide.
There are several ways to create light emitting objects. The simplest is to place a light entity into your map. If you do nothing, it has a default value of 300 and emits white light. If you think of the light value as the wattage for an incandescent light bulb, you are not far off target. The section on the Light entity in the Entities Description Appendix contains specific information on using light entities. See Visual Effects/Dynamic Lights.
If you only plan on using id textures in your maps, simply use the textures surrounded by a white box in the texture window. Many of them have their light values as part of their names: Example: ceil22a_5k. This would be a small, square light with a light value of 5000. There is not a direct correspondence between the light value of a texture light and an entity light.
If you want to make your own lights, either with new, custom textures, or changing the light and/or color values of the emitted light in existing id textures, plan on learning your way around the shader files. See Models/Shaders for more information.. Place the new lights in unique directories. Example: Mymapname_light\skull_light_2k. Use the q3map_editorimage key to make multiple light intensity versions of your new lights.
Generally speaking, very small lights need to have very large values to look right (a 32x32 pixel light could easily have a surfacelight value of 10,000 or more). As the surface area of the light becomes larger, the amount of light needs to be substantially reduced for it to look right in the world. A word of warning, though. Very large glowing surfaces (other than skies) can look odd in the game world, especially if they are made from a repeating texture. The light source will appear to be generated from the center of the brush with the glowing texture.
Squib Lights are light emmiting hidden objects built into Anachronox. Squib Lights can be placed anywhere in a map or actually attached to a models tag surfaces. The light emitted from these objects have an area of effects and are great for changing the light for specific instances. Since these lights do use an entity to emit light it is not recommended to use a lot of them on one map as this will slow down the game. For more information on using ob_squibs and attaching them to models see Planet/Lighting Entities. Also see Visual Effects/Dynamic Lights.