LMS color space

LMS color space is effective, for each of the human viewer of colored lights or colored surfaces of the color space. He is a physical-mathematical representation of the underlying biological and psychological process. The LMS color space is the actual Zapf color space and basis for true color reproducing technical systems.


Any colors can be represented (for a human observer ) after the first Grassmann 's law through three primary colors. Therefore, any shade can be assigned a color point in a three dimensional vector space. This approach is the abstract symbolism which was necessary for coloring methods, colorimetry and technical treatment of colors, such as the color reproduction of this screen. Color spaces are adapted to different functions and a CIE color space, RGB color space and the CMYK color space, or the LAB color space in use.

A radiation in the visible range directly from a light source or indirectly from a surface exerts a color stimulus. This caused the three cones of the human visual system, a color stimulus, a color value. In the subsequent process in the body, this is perceived as color. For the reaction of the color centers " stimulated " is the term tristimulus common, although this term is used for the modified Normvalenzen.

To illustrate the " Spektralvalenzen " the pins are shown in the diagram. The values ​​have been measured directly in human L-, M - and S-cones, as well as human fingers with a microscope spectrometer. Additionally, the measured values ​​are shown in rhesus monkeys that were carried out by Bowmaker ..

The color receptors of each eye have an individual spectral sensitivity. This is formed in the process of perception to a certain sensation in the nervous system. This applies to every eye, whether animal or human, and the subsequent nervous apparatus. Each normalfarbsichtige man has three types of " color-sensitive " cones. These are referred to by the position of the maximum of their sensitivity as L-, M - and S-cones.

In German literature and K - pin is set for S cones at times. The L cones take primarily the color stimulus of the radiation from the long wavelength red range true, the M cones the middle green area and the S-/K-Zapfen the short wavelength blue region of the spectrum. For the reception of the vision system also includes chopsticks, English: rods.

Although there are individual differences in the spectral absorption properties of these cones, which produces about by genetic variations, and the specific influence of lens or vitreous inside the eye, which is determined by personal coloring or around the age by turbidity, tune the absorption curves for all normal-sighted people in good agreement.

The totality of the perceptual color stimuli, so the colors will ultimately mapped to these three parameters L, M, S. In the " objective world " there are spectral distributions that are with everyone ( even continuous level ) wavelength between about 380 nm and 780 nm color stimuli, each with an intensity of 0% to 100 %.

Sometimes three causative color values ​​according to the peak sensation with R (ed ), G ( reen), denoted B ( lue). Since this can lead to confusion with the coordinates of the RGB color space and P, D, T is common, where the precipitated receptor in Farbenfehlsichtigen, so P [ rotanopie ], D [ ichromasie ] and T [ ritanopie ] is used. Another system uses the Greek letter ρ, γ, β. It Rho stands for L or R, M or G for gamma and beta for S-cones or the blue-sensitive.

It can form a three-dimensional vector space, which is spanned by the three axes L, M, S.

The incident, the eye striking color stimulus has the spectral composition of f ( λ ), absorb the receiving pin with the spectral l ( λ ), m ( λ ) and s ( λ ). This (cones ) spectral values ​​are the color values ​​in the color equations and give the spectral color stimuli.

This gives the to the nervous system led color stimulus, with the necessary three color values, or depending on the interpretation of the color locus of the color in the color space.

A spectral color in the color measurement, a sufficiently narrow section of the spectrum and the bandwidth Δλ nearly 0 nm, in practice, this width is at best be 1 nm.


The measurement of the individual absorption spectra of L ( λ ), M ( λ ) and S ( λ ) is a complex measurement task. The foundations for the CIE systems laid the measurements and work of Maxwell, King, Dieterici and Abney, which were summarized in 1922 by the OSA ( Optical Society of America ) and published in an edited form. At this time, the possibilities and the accuracy of the measurements were inadequate, have David Wright (1928) and John Guild ( 1931) independently launch new and more accurate mixing tests (color matches) and photometric comparisons performed and created a new basis of basic data. The respective data agree very well with each other and confirm it in the context of accuracy, the old measurements. In 1931, data from the CIE recommended internationally as a database Wright and Guilds. Stiles, Burch and Speranskaya delivered later further data which increased the system and also confirmed the measurements by Wright and Guild. Bowmaker eventually led directly to the object with a microscope spectrometer measurements of the absorption properties of the pin through. The direct measurements showed that up to this point only indirectly computable LMS sensitivity values ​​very well, so matched the actual values ​​with the measurement results.

Since the original LMS color space for technical purposes contains some drawbacks that Zapfenvalenzen LMS were replaced by the virtual Normvalenzen XYZ and based on the CIE 1931. The number of individuals was limited from these technical reasons in the 1930s to a total of 17 selected people. Guild itself had carried out measurements on 7 persons. This is still regarded as a further disadvantage and potential source of error. Nevertheless Stiles in 1955 found in subsequent measurements, that the data of these 17 people represent an adequate representation of the 2 ° standard observer and guarantee. But since have enforced the values ​​CIE standard today, is corrected mainly with transformations such as the DIN99 color space using the computer technology.

To take into account all normal sight, differ from the standard observer, there are additional data sets ( standard deviate observer, standard deviation observers) to the CIE data for both the 2 ° - apply as well as for the 10 ° standard observer.