ANSI White

The basic ANSI C78.377-2008 quadrangles (red) with centers (blue +).

ANSI C78.377-2008 is a standard developed by the American National Standards Institute (ANSI) and the National Electrical Manufacturers Association (NEMA) in 2008 to standardize the description of tints in LED's and Solid State Lighting. It sets up 8 points with coordinates based on correlated color temperature (CCT), and offsets from each coordinate that describe quadrangles on the chromaticity chart. These are shown in the graphic as red dashed rectangles.

1. 6500K
2. 5700K (cool white)
3. 5000K
4. 4500K
5. 4000K (neutral white)
6. 3500K
7. 3000K (warm white)
8. 2700K

This standard was adopted by companies like Cree and Philips Lumileds to describe the tint of their LED products. They divided each ANSI quadrangle into four quadrants to get bins like 1A, 1B, 1C, and 1D being divisions of quadrangle 1 (6500K). Towards the cold end of the spectrum a non-ANSI quadrangle, quadrangle 0, was added. Tints lying outside of the ANSI standard, above and below quadrangles 0, 1, 2, 3, 4, and part of 5, are given names like 1R, 1S, 1T, and 1U. Cree subdivides regions 5, 6, 7, and 8 into even smaller subdivisions to get bins like 5A1, 5A2, 5A3, and 5A4, while Lumileds would call all of those 5A.

Chromaticity chart with ANSI quadrangles by CCT and Cree divisions and subdivisions

Further reading

• NEMA website ANSI standard can be downloaded after registering for free.
• Wikipedia: Chromaticity
• Wikipedia: Color temperature