Difference between revisions of "ANSI White"

Latest revision as of 19:57, 1 February 2016

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), the American National Standard Lighting Group (ANSLG), and the National Electrical Manufacturers Association (NEMA) in 2008 to standardize the description of tints in LEDs and Solid State Lighting. It is based on a similar standard developed for fluorescent 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 as shown in the graphic to the right.

6500K (daylight)
5700K (cool white)
5000K
4500K (neutral white)
4000K
3500K (warm white)
3000K
2700K (soft white)

This standard was adopted by Cree (as well as most others, to some degree) to describe the tint of their LED products. Cree numbered the quadrangles 1 through 8 starting with 6500K. They developed the concept further by dividing 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. This gives a total of 16 different bins in one ANSI quadrangle. In the graphic below, the ANSI quadrangles are in red with the Cree bins overlaid on them (click for a larger version).

Luminus does something similar by subdividing the standard ANSI quadrangles and adding their own outside of those limits. Nichia, Samsung, and Osram also use ANSI's scheme for at least some of their LEDs.

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

Side-by-side comparison of a number of flashlights and tints. Click for full caption.

@@ Line 1: / Line 1: @@
-[[File:Ansiwhite.jpg|thumb|400px|Chromaticity chart with ANSI divisions by CCT and Cree division and subdivisions]]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 regions based on correlated color temperature (CCT), defining centers at certain coordinates and offsets from each coordinate that describe a "rectangles" on the chromaticity chart. These are shown in the graphic as red dashed rectangles (easier to see at full size).
+[[File:Ansiwhite.png|thumb|300px|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), the American National Standard Lighting Group (ANSLG), and the National Electrical Manufacturers Association (NEMA) in 2008 to standardize the description of tints in LEDs and Solid State Lighting. It is based on a similar standard developed for fluorescent 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 as shown in the graphic to the right.
-# 6500K
+* 6500K (daylight)
-# 5700K (cool white)
+* 5700K (cool white)
-# 5000K
+* 5000K
-# 4500K
+* 4500K (neutral white)
-# 4000K (neutral)
+* 4000K
-# 3500K
+* 3500K (warm white)
-# 3000K (warm white)
+* 3000K
-# 2700K
+* 2700K (soft white)
-This standard was adopted by companies like [[Cree]] and [[Philips Lumileds]] to describe the tint of their LED products. They divided each ANSI rectangle into four quadrants to get bins like 1A, 1B, 1C, and 1D being part of rectangle 1 (6500K). Tints lying outside of the ANSI standard, above and below the rectangle, are given names like 1R, 1S, 1T, and 1U. Towards the cold end of the spectrum a non-ANSI rectangle, rectanble 0, was added. 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.
+This standard was adopted by [[Cree]] (as well as most others, to some degree) to describe the tint of their LED products. Cree numbered the quadrangles 1 through 8 starting with 6500K. They developed the concept further by dividing 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. This gives a total of 16 different bins in one ANSI quadrangle. In the graphic below, the ANSI quadrangles are in red with the Cree bins overlaid on them (click for a larger version).
-==Further Reading==
+[[Luminus]] does something similar by subdividing the standard ANSI quadrangles and adding their own outside of those limits. [[Nichia]], [[Samsung]], and [[Osram]] also use ANSI's scheme for at least some of their LEDs.
+[[File:Ansi-white.jpg|thumb|left|400px|Chromaticity chart with ANSI quadrangles by CCT and Cree divisions and subdivisions]]  [[File:Ledtints.jpg|thumb|300px|Side-by-side comparison of a number of flashlights and tints. Click for full caption.]] <BR CLEAR="ALL">
+==Further reading==
 * [http://www.nema.org/stds/ANSI-ANSLG-C78-377.cfm NEMA website] ANSI standard can be downloaded after registering for free.
 * [http://en.wikipedia.org/wiki/Chromaticity Wikipedia: Chromaticity]
 * [http://en.wikipedia.org/wiki/Correlated_color_temperature Wikipedia: Color temperature]

Difference between revisions of "ANSI White"

Latest revision as of 19:57, 1 February 2016

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