All colors of a color model, which can actually be issued by a coloring technique, are three-dimensional - illustrated - as the color space. Each coloring method has its own color space. A list of all color coordinates of a color model is the body color.
All procedures and related equipment and materials that can add color to represent, are called coloring methods. Such methods are printers, monitors, includes prints, art prints, paint or manual color application.
- 2.1 color perception
- 2.2 Transmission of additive to subtractive
- 2.3 color differences and equidistance
- 4.1 color difference formulas
- 4.2 Variation of the color spaces
- 4.3 Economic importance of the color difference
- 4.4 color pattern and color catalog
- 4.5 Variants of the color space form
- 4.6 Some color spaces and color models
- 4.7 color values when viewing web pages
- 4.8 color scheme for display
- 4.9 The CIE systems
- 4:10 systems outside the CIE
- 4:11 color components
- 4:12 Color / Image Appearance Models (CAM / IAM )
- Different representations of color models and color spaces
Color space animation
Color mixture of red, green and blue
Color mixture of cyan, magenta and yellow,
Color mixture of red, green and blue
HSB model: change in each one of the three necessary variables
Colors, referred to more accurately as colorimetry color valence, based on color stimuli that differ in their spectral composition. By the need to define precisely the differences, various color models have been developed. These are based on Grassmann's laws. Each color can be obtained by a color name (descriptive words ), but be defined by the numerical locus. Depending on the color model can be uniquely described by brightness, saturation and hue, but even after Hell-/Dunkel-, Rot-/Grün- and yellow / blue value with three such sizes the color.
A color system is the classification for the arrangement of color stimuli that produce colors in different ways: by " mixture " of light than light colors or the use of colorants on a support material as body colors. Depending on the application, a different number of primary colors to be used: at least three, but four or more coloring substances are used. However, these are no longer independent of each other.
The color system always represents only the basic principle of color mixing, never the technical implementation of the coloring method. This is most evident in the color white. This can be blinding and dazzling, but also dull and dull depending on your choice of coloring method. Both types represent White, not contradict the underlying color system.
The color model is created from the abstract color system mostly for practical three-dimensional representation, which can be of different shapes. Within the models are all the colors of unique number values , the color loci assigned.
If the chromaticity of a color with the help of a software change within the same color model so may result in a loss of information. Even through the transmission to the coloring method caused this loss of quality. This can not be prevented only reduced. The number of levels to increase differentiation within the color model and an appropriate color management are most effective. The color model used is the carrier of the information of sharpness and so in turn the model influences the outcome of the focus in photography.
The body color is the geometric body with which the color model can be represented. For Philipp Otto Runge was the ball, by Erwin Schrödinger of the color bodies by Siegfried Rösch was suggested that Wilhelm Ostwald chose the double cone and Harald Küppers the rhombic dodecahedron. It is a systematic arrangement in the dense, continuous connection of all color loci of the underlying color system.
The locus is the point in or on the body color, and is described in color space with suitable coordinates in position. This place represents the agreed color. Color are continuously written in color spaces, their real presentation in color atlases, however, is naturally only intermittently possible.
The color space is a color-imparting method comprising all possible colors which can be displayed in the color model. In implementing the color display, all coloring methods are necessarily lossy. Although some colors have a specified color, but can not be represented with the available colorants. The displayable colors form in the color model, a body, referred to as color gamut. Said body is called the color space, the color space can fill the entire color model in the ideal case. Color spaces are used for visualization of differences between an ideal state and the required reality.
- The amount of the presented colors in a color space is the totality of all color stimuli that are perceived by the sense of sight. Thereby forming, for example, the amount of colors that are visible on a screen, a color space, in this case, the device color space of the screen with the coordinates of R (ed ), G ( reen) and B ( lue).
- It can span the respective defined and limited measurement space of these colors also several (physical ) base colors. The basic colors of a color model only those valences may be selected that are defined by the Grassmann laws as independently.
- Colors are quantified by a color model. A color model is a coordinate system with the coordinates corresponding to selected basic color valences. The figures are position vectors of the color model, their information may be given in the form of a tuple (here 3 -tuple ).
- Color spaces are a necessary tool in colorimetry, in which unit-related conversion of reproductions and design ( color management ) and the subject of various color theories. A color space is subject to as a "model of reality" to the limits of its definition.
- The aim of the design of color spaces is to achieve within the model boundaries accordance with the color perception of the human being. This input device and output device must be coordinated. Improved coloring methods in turn creates new demands on the color management.
The human eye has three types of cones as a rule, allow a color-sensitive receptors seeing " in color". The spectral sensitivity of the pins, in turn, covers from a part of the interval of visible light.
Color vision can be described in three dimensions. This finding is based on the 1st Grassmann's law, that is a color space ( here as an area of colors) in three dimensions. The reason for this is the stimulus intensity on the three color receptors. The color stimulus ( colloquially " the color" ) is represented by three vector lengths for color coordinates, a point in the color space. The three-dimensionality was painters have long been known and has been described by Thomas Young first time with the three-color theory.
In the reenactment of a body colors spektralgerechte playback is hardly possible, since different materials or equipment systems or the various coloring methods leave hardly the same impressions, also the (real) color of ambient conditions is affected. By the phenomenon of metamerism is disclosed that color may arise from different kinds of three primary colors. So colors with three Grundvalenzen for practical purposes can usually be represented with sufficient accuracy, as long as the conditions are not changed too much. The variety of spectral compositions is mapped to the individual on three perceptual tap values .
Transmission of additive to subtractive
Through the self-luminous properties of the additive color mixture results in a high dynamic range. The " brilliance " of this luminance not only provides a high sharpness, but also allows for color representations that are possible only through additive color mixing.
In subtractive color mixing ( color bodies ) may be used because of other primary colors, other colors than the additive color mixture is shown. The color spaces of devices with additive and subtractive color mixing are fundamentally different. Both involve the other hand, also many colors that they can be displayed together. Because of these similarities, a color separation is possible at all.
The problem arises when the coloring methods are considered no longer under standard conditions. The subtractive color mixing "lives" of reflected light, while the additive color mixture used self-luminous colors. So both react differently to the change of ambient light - here even the best color management (still) do nothing.
A common practice case for color separation is the conversion of RGB data (additive, such as the screen ) in the CMYK system for the pressure ( subtractive). The transition from additive to subtractive mixing is a simple transformation of the color space of one device to another, since the non-linear mixing behavior of the printing pigments ( possibly with a color cast ) must be considered as well as the color of the paper. Since color cover when printing is non-linear color space conversion is considerably more difficult. This special color spaces (ICC ), or created for this purpose, the LUT ( look-up table ) are necessary.
Another problem with this conversion is the use of different amounts of ink, three or four colors, or more like the use of spot colors.
Black is also mostly used in printing for the following reasons:
- Set on subtractive are displayed in dark gray with a black or coloring method, it is more economical to use black as a separate color. The representation of black of only three colors is very complex, expensive, sometimes impossible due to the actual absorption of the color pigments and is therefore ( almost) only used in color photography.
- The subtractive color mixing lacks the high contrast range, which is the additive mixing own. The addition of black improves the contrast subjective impression (the printer speaks of depth).
- As printing methods are raster-oriented method, creates strong subjective loss of sharpness when displaying delicate colors. The grid size is increased, thus the detail image contains less information that is interpreted by the eye as loss of sharpness. The admixing of black produces a subjective balance this loss. In contrast to print gray scale values for the same reason may often be generated from better black composite colors instead of.
Due to problems such as non-linear color behavior, amount of color differences of luminance, subjective sharpness balancing a color separation is very costly.
In the photo reproduction is the closing date in the clear advantage because they (namely RGB) uses the same color model as the input devices (scanners, cameras) and the control device (screen ). Only for the final picture ( coloring method) must be transferred to the subtractive color mixture of the additive.
Color differences and equidistance
There are no devices that can detect or generate the entire gamut of human perception. MacAdam was working on a color metric which should allow the equidistance of color differences, the color differences are to be perceived as the same visually. Such colorimetry with the result that the parameters for the color differences from the situation in the chromaticity or chromaticity depend.
The human perception of color differences in a technically defined color spaces represent results in the CIE color space tolerance ellipses of the same color perception, known as MacAdam ellipses. Here is the starting point for the development of higher colorimetry. Further work in this area was done by Walter S. Stiles and D. Farnsworth. Stiles developed a line element, that equally spaced perceived color differences mathematically equidistant describes ( at the same distance ). Farnsworth developed a non-linear transformation that deforms all MacAdam ellipses to circles. From the CIE UCS color space has been created in several versions as a solution first. Later (1976 ) were both the Lab color space ( for body color preferred) and the LUV color space (for light colors preferred) presented as equally spaced color spaces.
Although already had Leonardo da Vinci made attempts to organize artistic colors that attempts were due to the lack of theoretical foundations appears fragmented. In 1800, at the time of Goethe's interest in color theory, the ideas about colors were very subjectively oriented. The aim was primarily to facilitate painters relations between colors. Examples which may be called Runge's color sphere.
By 1900, required the progressive industrialization numerical color, even without currently existing color palette is the definition of a design are possible. To bring order to this goal in the variety of shades of color were preceded by the work of Munsell, Ostwald, Rösch, Schrödinger. Important physical principles derived from Maxwell, Young, herring. Measurements of the color stimulus were carried out in 1928 by William David Wright and Guild.
As a result of this work the first standardization of a color space by the International Commission on Illumination ( CIE) was possible. Elaborations of the CIE recommendations that enable the world by the special committees of the device classes vote.
The first color model was proposed in 1931 by the CIE tristimulus with the model. This model was based on the averaged 2 ° standard observer ( from a group of 17 subjects ). This 2 ° visual field corresponds to the size of the retinal region with the densest packing of cones ( color receptors ) in the human eye, the fovea ( fovea ). Since the sample surfaces for color matching, however, were greater in 1964, the tristimulus model for the 10 ° standard observer has been introduced. Since the present scale short color screens, for example, MP3 players, portable game consoles and mobile phones will be very small, the 2 ° standard observer from 1931 for small viewing angle is regaining importance. As early in the 1940s MacAdam a problem in the xy surface fixed: the perceptual non-uniformity in the XYZ model (also called the (shoe) sole ), led to the xy plane through the transformation into the UCS system (Uniform Chromaticity Scale, Yuv and Yu'v ') was deformed so that the color distances to the ideal of perceptual uniformity (equality of color distances in the color space and perceived color distances ) were heavily approximated. In the original xy plane the size of the tolerance ellipses varies approximately by a factor of 20, with the smallest ellipse in the blue area and the largest ellipses in the green area of the graph. In the UCS system from 1976, this non-uniformity was greatly reduced. The size of the tolerance ellipses in CIE 1976 UCS diagram ( u'v ' Diargramm ) varies only by a factor of approximately 4 This is according to MacAdam the best value that can be achieved by transformations of this kind.
The types of paint surface eliminates the third axis of the bright reference value A, which is equated with the tristimulus value Y. The lightness value is also referred to as L ( Luminance ).
1976 by the CIE in both the L * a * b * were - and the L * u * v * approved model. In both systems, the alignment of the color differences in the color space is achieved in the performance by using two systems of L * a term that includes the third root of the ratio of the tristimulus value Y, and the white point Yn. This term is used to mimic the logarithmic brightness perception of the human visual system. This non-linearity flows in addition to the values of a * and b * and u * and v *. The non-linear transformation is reversible. The L * a * b * model preferably applies body colors, and can be held in Cartesian coordinates into polar coordinates (more specifically, cylindrical coordinates ), in the form of the L * C * h ° system, are presented. The cylindrical form of presentation gives the additional coordinates C * ( chroma ) and hue angle h ° (hue ). For light colors, the L * u * v * system is more suitable, since this has an associated color chart types. L * u * v * can also be converted into cylindrical coordinates, with the additional parameters C * ( chroma ), huv (hue ). A third parameter, suv ( psychometric saturation ), can, in contrast to the L * C * h ° system are also derived.
The development and standardization of photographic and electronic devices brought a number of specially selected RGB color spaces (sRGB, Adobe RGB 1998), the phosphors used ( phosphors) for red, green and blue and realizable filter ( TFT screens ) adapted were. The goal is to be the so displayable color stimuli justice. In representations on the Chromaticity ( xy surface of the CIE) RGB systems are areas of color within the limits of the phosphors (material realizations of the excited electron radiation in the required spectral range ). Since the xy surface (shoe sole, shoe s: Horseshoe ) By definition, the maximum perceivable colors defines the RGB color must be within the Spektralfarbenzuges.
With the progress of mathematical topology, on the other hand, the increasing demands of reproducibility of the color impression in the electronic recording and reproduction technology, further adaptations to the reality will be necessary. Clearly, this trend to the color difference formulas ( AE ) that define the measure in the color space and modified in 1976, 1994 and 2000. A similar trend set the ICC profile is application-oriented, with these also formed device-oriented working spaces. In color management, it is with different equipment categories to determine the specific color spaces of devices possible for the adjustment of the color reproduction / implementation. By Matrix or LUT ( look-up tables), the color locus of the special working space of the source is (if possible ) comprehensive color space transformed into a suitable as an intermediate result, again to determine from this " gap " (consignment color space) the color point in the working space of the target device.
30 to 40 color models have been created so far. These differ in the intended area of use. Accordingly, they can be categorized.
- Technical and physical models that produce the color stimulus from the real or idealized materials coloring, as RGB
- CRT monitor, color television picture tube
- Liquid crystal displays
- Plasma screens
- PAL TV
- NTSC TV
Color difference formulas
Color distances can be determined by quantitative color difference formulas. The result of such a formula, AE, is considered fairly reliable indicator of perceived color differences. The since the introduction of the Lab color space in 1976 changed color difference formula AE in 1976 and the development of their successors shows that there are by no means a trivial problem. AE 1976 was determined from the Euclidean distance between the color locations. This simple calculation has been significantly developed and expanded to CIE94 ( AE 1994) and published in 1995. CIE94 was in 2000 again extended to CIEDE2000 ( AE 2000). CIEDE2000 is strictly speaking a hybrid model, since not only the color difference formulas have been changed, but preceded by a simple transformation of the LAB color space of the actual color distance calculation. The way the color space adjustment has been fully implemented in the DIN99 color space. The color difference formula remains untouched and is under construction with the original AE 1976 identical. Another common color difference formula is AE CMC ( l: c ), developed by the Colour Measurement Committee of the Society of Dyers and Colourists of Great Britain ( Color Measurement Committee of the Society of Dyers and Colorists UK), which was published in 1984.
In the early development also earmarked factors were introduced. Especially for the textile industry ( AE CMC ( l: c ) ) special correction factors were introduced into the calculations of the color difference. These can be adapted for determining the distance in the color graphic applications.
Variation of the color spaces
A special position is occupied by the DIN99 color space. It was first published in 1999 as the color space according to DIN 6176 and later developed into the DIN 6176:2001-03. Instead of adjusting the color difference formulas a complete transformation of the CIELAB color space was made. This allows color differences as Euclidean distances on the same principle as AE of the CIELAB color space determined.
Economic importance of the color difference
The color difference is for contractual arrangements ( What color should " Ferrari red " have car paint? ) And also for the color matching of interest. Particularly common for colors with a high recognition value, as with many brands as corporate identity, a consistently flawless color (re) production and reproduction is very important. In the field of transport, colors are exactly prescribed for light signals such as traffic lights. You must be accordingly supplied by the manufacturer with original colors. For " white- gray" ( almost achromatic ) colors in addition there is the problem that even the smallest deviations clearly perceptible color cast ( " bite " colors of pants and jacket itself ) can cause what in many areas, such as when to buy any wall color in cutting parts of clothing or in automotive coatings is not acceptable. Economically lead to serious consequences for the manufacturer or supplier.
Color pattern and color catalog
The representation of color spaces is often implemented by abstract topographical descriptions. An alternative form color patterns in a color catalog. However, for technical reasons are presented only selected colors. For all colors of a color space, so the continuous transition of all color loci is this types of light possible, but practically impossible.
Variants of the color space form
A color space describes the colors from an input device ( sense of sight, camera, scanner) or an output device (monitor, Photosensitive, printer, projector) can be identified, respectively, shown under specific conditions. As each person perceives colors individually, also devices, at least in classes of devices, different color spaces in which they register or colors represent. Such individuality is due to production variation and differences in construction.
More deviations arise from optical effects, which are not considered in the metrological detection of color spaces:
- Input devices ( sense of sight, camera, scanner) change to a large extent their color sensitivity in substantial differences in brightness. Since this case is more likely in practice is more the rule than the exception, can, produced under standard conditions color space represent only a guide.
- Output devices (monitor, Photosensitive, printer, projector) to work under certain lighting conditions. Depending on the color temperature of the ambient light, the colors are perceived by the eye differently. Only one output device that is used under standard light conditions, provides results that are close to the color space previously determined.
A large part of this difference is corrected by automatic image optimizations. This metameric effects are used, the - explained simply - colors simulate. These color simulation is highly sophisticated and integral part in everyday life. A typical example is inkjet printers that laminate by a high proportion of black deficiencies in the presentation of colors.
Some color spaces and color models
In many applications, specialized models and their spaces play a role:
- LMS color space - the physiological color space, which is based on the spectral sensitivities of the L-, M -, S-cones.
- XYZ color space - designed by the CIE originally been imputed standard color space to computational coordinates X, Y, Z, which are created from Zapf sensitivities.
- RGB color space - computer monitors, Internet standard.
- CMYK color model - Desktop Publishing, pressure final stage.
- HSV color space with the variants HSL, HSB, HSI - design, documentation of painting, video art.
- Lab color space - CIE XYZ color space from derived, which also includes all perceptible colors; and its development DIN99 color space.
- LCh ° color space called no other color space in the strict sense, but the presentation of HSV, LUV or LAB in polar coordinates.
- I1I2I3 color space - computationally optimized area of image processing.
- YCbCr color model (sometimes called short YCC, see below) - digital television, digital both PAL and NTSC digital, DVB, JPEG, MPEG, DVD-Video.
- XvYCC - compared to YCbCr extended color space, which uses the full 8 bits per color channel and can be used for new flat screens.
- YPbPr color model - analog HDTV, component analog video.
- YUV color model - for both analogue PAL and NTSC.
- YIQ color model - outdated, formerly used for analog NTSC.
- YDbDr color model - for analog SECAM.
- YCC color model - Kodak Photo CD.
Color values in the representation of web pages
The specification of the color values in the Cascading Style Sheets is a good example of a three-dimensional color model. Defines the values in the system of an RGB color model with red, green and blue. The application of color space in CRT monitors is the color space of the screen with the typical phosphors phosphorescence in electron excitation of red, green and blue. The underlying standard is sRGB, which is used as primaries as defined by the ITU -R BT.709 - 5 standard color coordinates.
In the " CSS ( rgb ) model " are for the background ( background ) of the field of site values between 0 and 255 defined (that is, 28 values). In the example,
- A " purple " with the following color values r = 255, for the ideal base color red in all its purity and strength
- G = 0 corresponding to a lack of basic color green,
- B = 229 specifies that the base color blue to 1.055 × ( 229/255 ) 2.4-.055 = 76 % proportionate strength to be involved (see the sRGB color space )
- R = 0 the need for basic color red,
- G = 255 Base color Green at full strength and intensity,
- B = 150 complementary base color blue in 1.055 × ( 150/255 ) 2.4-.055 = 24 % proportionate strength (24 % 76 % = 100%)
By using software of the PC, the color values of the CSS style sheets are translated. The three display phosphors for red, green and blue are controlled in the beam intensity. At a sufficient distance from the screen this color stimulus leads the user to a color stimulus in his "individual Zapf color space ". So when looking at the website gives the desired color effect. The Zapf color space of the viewer ( " That " of the "now", " this " screen viewing. ) Is a LMS color space of the viewer " at individuals ".
Color scheme for display
When mixing three primary colors ( RGB system ) can set colors with conventional display devices such as CRT and LCD screens are produced only in the context of emission sources or by absorbing colorant ( filter). Color systems with wavelength of the same color and brightness ( HSV) are better suited to describe the pure colors; the technical interpretation, however, is difficult. The special position of Purpur-/Magentafarben is in the horseshoe-shaped CIExy or CIELuv - color diagram by the final straight line connecting the extreme blue value with the outermost red value, recognizable.
The CIE systems
- Tristimulus of 1931 ( 2 ° standard observer, English:. 2 ° standard observer ), 1964 supplemented with new records for a field of view of 10 ° ( 10 ° standard observer, English:. Supplementary standard observer 10 ° )
- CIE XYZ color space system ( chromaticity diagram ) Standard color chart
- Since the Spektralwertfunktion y ( λ ) corresponds exactly to the brightness sensitivity in Zapf See, the ( non-normalized ) coordinate Y as brightness (luminance) are used, this should be a constant better "A", will take Y are chosen
- Coordinates: Y, x, y, or in the chromaticity diagram only x, y
- Linear transformation from CIEXYZ to reduce the location-dependent non-linearity of the perceived color differences
- Defined only 2D color distances
- Although often the same spelling (YUV instead CIEYUV or CIEYuv ) not related to YUV from video technology!
- Coordinates: Y, u, v
- Linear transformation of the CIEYUV ( YUV ) color space
- Another linear transformation in order to reduce the location-dependent non-linearity of the perceived color differences
- Defined only 2D color distances
- Coordinates: Y, u ', v'
- Non-linear transformation of the CIEXYZ color space refers to the CIE 1964 UCS color space ( CIEYU'V ') for the white point of a, the transformation is reversible
- Spectral line is outer boundary of the color diagram, therefore the absolute saturation (relative to the spectral line ) of a color is measured
- Color mixtures lie on straight lines in space, therefore very suitable for colorimetric calculations and representation of additive color mixing, how to describe self-luminous sources ( light colors)
- Color diagram psychometrically oriented and geared to the opponent color theory, similar to CIELAB
- Focus equidistance of color perception, similar to the LAB color space
- Coordinates: L *, u *, v *
- Non-linear transformation of CIEXYZ, the transformation is reversible
- Color diagram psychometrically oriented and based on the opponent color theory
- In contrast to the CIELUV in CIELAB measuring the absolute saturation (relative to the spectral line ) is not possible, because the spectral line in the LAB color space and does not have a preferred location in the diagram, instead of the saturation, the chromaticity of a color is represented
- No color table available
- Ensures good equidistance of color differences by the nonlinear transformation
- Particularly for the description of non-luminous colors (body color ) used
- Coordinates: L *, a *, b *
Systems outside the CIE
- DIN99 color space ( color space according to DIN 6176 ), since 1999 Coordinates:, ,
- Alternative to the color difference formula CIE94 comparable equidistance
- However, subsequent development (DIN 6176:2001-03 ) improved equidistance. The currently best variant ( DIN99d ) is qualitatively between CIE94 and CIEDE2000
- Special position with respect to all CIELAB successors, instead of the color difference formulas, the entire color space transforms
- Adaptation of, dark colors more heavily weighted, bright compressed
- "Round" shape ( Gleichabständigkeits - ideal shape ) by radial compression of the Bunttonebene, therefore:
- Color distances near the achromatic axis are determined by the radial compression of saturated colors more heavily weighted (similar CIEDE2000 )
- Calculation easier than CIE94 and CIEDE2000, is calculated as the color space is transformed and the color difference formulas remain unaffected In the case of variant a part of the transformation DIN99d already in the XYZ color space takes place
Color components that are essential to the CIE color space systems:
- CIE XYZ tristimulus values or
Color / Image Appearance Models (CAM / IAM )
Currently, intensive studies and research in the field of "Color Appearance Models " (CAM ) to German about: models for the appearance of color, and " Image Appearance Models " (IAM ) to German: powered models to the appearance of images. Since the mathematical descriptions that calculate only colors and color differences, higher levels of human color perception does not take into account more advanced models are required, since a variety of other factors may have a strong influence on the overall impression. The developments of CAM and IAM arise the question: "How will a particular color or an image in the general context of the near and far an image" phenomena such as simultaneous contrast, adaptation to the ambient brightness and their variation over time, reducing the spatial resolution at Twilight ( mesopic vision ) and night vision ( scotopic vision ) namely play an important role in color perception.
A very common problem in this context is the fundamental contradiction between sharpness and sharpness perception. IAM are a step towards a solution to this conflict, because the processing of detail contrast, color contrast, etc. is taken into account separately in these models.
Is basically the first CAM. It is already taken into account adaptation to the white point ( by means of transformation, such as von Kries or Bradford - matrices), as well as the compression of the brightness perception. The development then led to CIECAM97s.
Is more accurate and more extensive in terms of the viewing conditions, etc.. The development was to CIECAM02 continued.
Generally provides more accurate values for color distances and wider consideration of things such as image brightness, color background image area, White Point, adaptation and simultaneous contrast.
Is a further step in the development. The latest member of these models is iCAM06. Will be considered based on ambient light things like local color adaptation, local brightness and ambient lighting, HDR, and time course of adaptation. The area of the IAM is entered. iCAM06 is in contrast to its predecessors already a full-fledged IAM, as for example, the white point adaptation and contrast calculations are no longer ( pixel by pixel ) but calculated spatially with a purely local model. Thus, areas of the image depending on the structure and composition also affect distant areas and thus change the overall impression of an image.