Known spectral data established by the CIE for four different types of light sources.

• A -This represents an incandescent light source like a tungsten filament.
• C -Represents average daylight.
• D50, D65, D93 -These D-series illuminants represent different times of the day in an outdoor setting. D50 is a standard for Graphic Arts Industry. As the number increases from 50-93 the light gets more bluish i.e. more bluish component is present.
• F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12 -These are the fluorescent light simulators. Most indoor lighting try to simulate the F2, F7 or F11 illuminants. F2 is a typical cool white fluorescent source. F7 represents a broad band daylight fluorescent source. Examples of F7 are GE and Philips daylight fluorescent sources. F7 represents a narrow band white fluorescent source.
  

See CIE (Commission Internationale de l'Éclairage).