CIE color spaces

The spectrum of the visible light
The electromagnetic spectrum includes the visible spectrum and the cosmic rays, gamma rays, X-rays, ultra violet and infrared, radio waves and electromagnetic waves. The visible spectrum is the part of the electromagnetic spectrum that can be seen by the human eye. Electromagnetic radiation within this spectrum is also called visible light. The visible spectrum is often divided into seven colors.

The visible spectrum has a wavelength between approximately 400 nm (violet) and 750 nm (red). That equates to a frequency of approx. 400 THz (red) to 750 THz (violet). The different wavelengths are seen as different colors. However, the visible spectrum does not contain all the colors that the human brain and eyes can distinguish. For example, variations are missing such as magenta: this color can only be created by mixing two colors.

International commission on lamination (CIE)
Mathematical relationships defining color spaces are essential color management tools, important when dealing with color inks, lighting, and recording equipment. The system was designed in 1931 by the International Commission on Illumination. The CIE is the committee that sets standards in the field of light, light sources, color and color space.

Color spaces
The CIE 1931 color spaces are the first defined quantitative relationships between wavelength distributions in the electromagnetic visible spectrum and physiologically perceived colors in human color vision. The CIE 1931 color space is still used today as the standard for defining colors and as an essential tool for color management and color comparison. As does the 1976 CIELUV color space. The figure below is a two-dimensional representation of colors of the same intensity (brightness), according to the standard CIE 1931 observation. However, a complete representation of colors is three-dimensional, with the z-axis representing the brightness.


The CIE 1931 color space chromaticity diagram with wavelengths in nanometers.

The three-dimensional image looks like a pyramid. This color space cannot be used to show the difference between the colors. That’s why this system was further developed to the CIELAB-system.The original CIE chromaticity diagram has been converted by LuxaLight to the RGB color space (see above CIE diagram). It is a reasonable approximation of the true CIE standard in terms of color rendering.

The color temperature is defined using the CIE color chart. This is a diagram that contains a triangle containing the primary colors: blue, green and red. A mixture of these colors produces the color white and this "color" therefore forms the center of the triangle. Within the center (white part) of the triangle is a curve, also called the "black radiator", which ultimately determines the color temperature of white light.

Color temperature
Measured on the basis of the color temperature, the color consistency is expressed in Kelvin (K). The color temperature reflects different shades of white light. Think of the various white tones such as extra warm white light, warm white light, neutral white light, cool white light, etc.

From the CIE 1931 diagram we have also converted the color temperature to the RGB color space and stated the corresponding color temperature.



Color spectrum
The color spectrum consists of the colors of the rainbow; with the color sequence red-orange-yellow-green-blue-indigo-violet (ROGGBIV), which corresponds to the falling wavelength (rising frequency) of the light waves.

From the CIE 1931 diagram we have converted the wavelength of each color (in steps of 0.1nm) to the RGB color space and stated the specific wavelength for each 5nm. Color spectrum, accurate perception of color with the corresponding wavelength.



Color consistency
The color consistency of lighting refers to the constant quality of the color of light. Color consistency matters for both colored and white light. For example, if different light sources are used during a project, it is important that there is no difference in the light color.

LED colors and wavelength overview

Color and wavelength overview:

700nm deep red - LED: some types, low brightness
680nm pure red - LED: ultra red, hyper red, deep red
660nm pure red - LED: ultra red, hyper red, deep red
655nm red
650nm red
645nm bright red - LED: 640-650nm
640nm bright red
635nm ’HeNe laser’ orange-red - LED: super red: 635nm
630nm ’HeNe laser’ orange-red - LED: HE red: 625-630nm
625nm orange-red - LED: HE red: 625-630nm
620nm clear orange-red

615nm reddish orange - LED: 615-617nm
610nm pure orange - LED: 609-610-612nm
605nm orange - LED: 605nm
600nm amber-orange - LED: 600nm

595nm amber (warm yellow, yellow-orange)
592nm amber (warm yellow, yellow-orange) - LED: 590-592-595nm
590nm Natrium yellow
585nm yellow - LED: HE Yellow,
580nm pure yellow - LED: HE Yellow,
575nm lemon yellow, become a little greenish

570nm yellowish green (between yellow and green)
565nm yellowgreen - LED: early types
560nm yellowgreen - LED: pure green, 562nm
555nm yellowish lime green
550nm yellowish emerald green
545nm emerald green
540nm emerald green

535nm pure emerald green
530nm pure emerald green
525nm pure green
520nm pure green
515nm green
510nm greenish turquoise (RGB pure green)

505nm greenishe blue / turquoise
500nm greenishe cyan
495nm turquoisish, a little sky-blue

490nm turquoisish, light sky-blue
485nm bright, a little azure-blue - LED: 480-485-488nm
480nm bright, a little azure-blue
475nm bright, a little greenish azure-blue
470nm bright blue with a liitle greenishe emphasis
465nm bright blue with a liitle greenishe emphasis
460nm bright blue
455nm bright blue
450nm pure blue - LED: Royal Blue

445nm diep blue / violet-blue
440nm diep blue / violet-blue
435nm diep blue / violet-blue
430nm violettish blue - LED: 626-428-430nm
425nm violettish blue - LED: 626-428-430nm
420nm deep violettish blue

415nm bluish-violet
410nm violet with bluish emphasis
405nm pure violet
400nm deep and more twilight color violet than 405nm

395nm deep royal purple
390nm deep royal purple with reddish tint
385nm twilight purple with deep red blur
380nm almost no longer visible purple