Illuminant Catalog

Access the library’s illuminant data, view spectral irradiance plots, chromaticity values, and Color Rendering Indices. Use this tool to familiarize yourself with different lamps’ spectral properties and color rendering characteristics. Copy spectral data into your device’s clipboard for use in other applications.


The library contains spectral data from light sources such as the Incandescent, Fluorescent, and LED Lamps. Some are measured using spectrometers, standardization organizations define others, and some are calculated from mathematical models. This app shows all the available illuminants in the form of their spectral distributions and primary colorimetric data.


At start-up, the CIE F1 illuminant data are displayed. Its spectral distribution and name, Correlated Color Temperature, CIE Color Rendering Indices Ra and R9, and IES TM30 Rf and Rg are shown on top.

Correlated Color Temperature is given with unit Kelvin and includes a Tint value, with a unit of 1 corresponding to a distance of 0.001 in the CIE 1960 (u,v) color space. The CIE F1 illuminant, for example, has a correlated color temperature of 6425 Kelvin. It has a Tint of +7Δ, which means it is located above the Planckian locus, with a more blue/cyan-ish color than a Planckian radiator would have.

Its general color rendering index Ra value is 76, and its R9 value is -47. The R9 value indicates how well a source renderers deep red, an essential element of skin color, being the color of blood. A value of -47 is not very good; a value of at least 0, but preferably 20 or higher, is required if you want people to look not sick with your chosen light source.

Developed by Illumination Engineering Society (IES) members, TM30 is a new standard to evaluate a light source’s color fidelity and gamut. The F1 illuminant, for example, has a color fidelity Rf value of 81 and a gamut area index of Rg of 90. The Rf value is obtained from 99 instead of 8 test samples, as used for the CRI calculation, and is a better prediction of color rendering performance. The Gamut Area Index represents the ability of a light source to enhance colors in a scene: colors look more vibrant if this value is above 100. The CIE LED-RGB1 illuminant, for example, has a gamut area of 107.

Source Selection

Below the plot is the source selection area. The sources are grouped into different collections; currently, there are the “CIE” and “IES” collections. Select a collection by clicking on the first tab of the light source list. At start-up, the “CIE” collection is chosen.

Select a category within the library with the second tab. The available classes vary with the source library but typically describe the emission type of the sources, such as Fluorescent, Incandescent, High-Intensity Discharge, and LED. The illuminant within a category is selected by clicking one of the source buttons. The currently selected button is highlighted.

Access Spectral Data

The spectral data can be copied to your device’s clipboard by clicking the spectral plot area. A regular click will copy the data as two columns of values, with wavelengths, in nanometer units, in the first column, and spectral values in the second column. The values can be directly pasted into a spreadsheet if you want to do calculations yourself.

Spectral values are normalized to a peak value of 100.00 and are given with a three-decimal precision. Holding down the “shift”-key while clicking the spectral area will copy a single column of spectral data over a range from 380 to 780 nanometers, with a step size of 1 nanometer, resulting in a total of 401 copied values.


You must be online to use this app, as the spectral data are fetched from the website when selected. Please check your internet connection if you don’t see any spectral plot or sources in the list.

The site uses JavaScript, as many web apps do nowadays, but if you have disabled JavaScript support for this site, you need to enable it to use its functionality.