Minecraft wiki entry for Light, associated text: In general, lighting due to blocks results in a higher brightness, which is balanced by the fact that light due to blocks effectively starts at 14 (solid light source blocks emit a level of 15, but that applies to the light source block itself) while sky light brightness is 15 outdoors. Light due to blocks also tends toward orange in the middle ranges, while sky light in the Overworld daytime is white.