Color combination is mainly an aspect of color syntax. To combine means to put one thing in relation to another, or several things together, so that the individuals lose significance and the meaning of the whole predominates. To combine also means to organize an ordered sequence. In some cases it acquires the sense of mixing or merging. However, mixing color pigments or lights normally yields just one color as the result of the mixture, and in this sense it cannot be termed a color combination, for which two or more colors in some relation must be perceived. Combination certainly is very closely connected to harmonization and coordination. Color combination, thus, is meant whenever there is more than one color associated, related, or harmonized with another: two colors already determine a certain kind of combination.
Color combination is, in principle, an aspect of color syntax. All perceptible colors can be organized in the so-called color order systems or models. This is usually made by means of three color variables or dimensions, for instance, hue, saturation, and lightness (HSL), or hue, blackness, and chromaticness (according to the Natural Color System), or hue, value, and chroma (according to the Munsell color system), or some other similar triad of variables. These color order systems allow for the precise identification and notation of colors and their arrangement in a logical way. Some of the systems even allow to predict the results of color mixtures. It is possible to compare color order systems to dictionaries, which assemble all the words available in a language in alphabetical order. So, color order systems arrange and organize all the colors that humans can see, produce, and use, according to certain sequences determined by the mentioned color variables.
This possibility of having the repertoire of all perceptible colors orderly arranged facilitates the selection of colors, by following certain criteria, in order to use them in artistic compositions, architectural works, or pieces of design. Only in few rare occasions (for instance, in experimental situations) colors are seen isolated; in the great majority of cases (both in nature and in human productions), colors appear in a context where there are also other colors. That is to say, every color is combined in a certain way with other colors. Such as words (which in a dictionary appear isolated) are combined with other words in order to make sentences and phrases with some sense and give origin to poetry, narrative, essay, etc., and also in the same way as sounds are combined according to the criteria and invention of a music composer to give origin to musical pieces, so colors are grouped in larger compositional units. And it is the context, the particular combination, the way in which colors are grouped together and related to one another, what gives a sense, a certain kind of signification or meaning, some utility to the whole composition and to each of the involved colors.
Painters dispose and mix colors in their palettes with the final aim of combining them in a canvas. Architects combine materials with different natural colors in a building or either use paints to endorse different parts of their work with color. Filmmakers and directors of photography decide about the color sequences that appear in successive scenes of the film. Clothing and fashion designers think about the chromatic combinations of the apparels they produce. Landscape designers choose and arrange the botanical species and other materials taking into account also color combinations. And it is possible to continue providing this kind of examples almost indefinitely, because there is practically no profession, discipline, or human activity in which color does not play a role.
If according to different authors and experiments, the number of perceptible colors may range, depending on various factors, from 2,000,000 to 7,000,000, the combinatorial possibilities rise to billions, even restricting them to the minimal expression of just two- or three-color combinations. Now, how are colors combined, with which kind of criteria, and in which type of contexts? At first, it is possible to talk about spatial and temporal contexts, depending on the colors being arranged simultaneously in an object or successively in a certain temporal sequence.
Syntactic Color Combinations
Spatial Color Combinations
That one color is applied over and inside another (interiority)
That both colors partially overlap each other (overlapping)
That they are juxtaposed one beside the other (juxtaposition)
The possibility of both colors being some distance apart is not considered here because in this case the color filling the separation, the background, appears as a third color. Also, there is no sense in considering a total superposition of both colors (both occupying exactly the same space), because in this case the result is just one color, and hence, this cannot be termed a color combination.
These three possibilities produce different results or have different consequences for color light and for color-pigment combination and also differ if there is a mixture or blending of the involved colors or if opaque color surfaces that do not mix together are combined. Combining colors imply that in some cases the colors are mixed and give origin to new colors. However, if the result of the mixture is just one color, this will not be a color combination.
If over an area of a transparent color filter A another piece of color filter B is set in relation of interiority, the outcome is two colors: color A and a new color, C, which is the subtractive mixture of A and B, while color B is missed.
If the colors overlap, the result is three colors: A, B, and C.
In the case of juxtaposition, there is no color mixture, so that the result is color A just besides color B.
Exactly the same happens with transparent inks and watercolors. Similar situations arise also when A and B are colored lights, but in this case color C is the result of an additive mixture. The situations are quite different with opaque color surfaces: in all cases, no new color C appears.
Additionally, in all situations – interiority, overlapping, and juxtaposition – phenomena of simultaneous contrast occur, so that, in reality, when considering colors A and B as seen in isolation, the perceptual result of the combination is, apart from the cases in which color C appears, colors A1 and B1, because when being combined each color is tinged with the complementary color of the other, or with the other color, according to the principles of simultaneous contrast; i.e., color sensations change from seeing color stimuli in isolation to seeing color stimuli in combination.
Now, if the combined colors have relatively small areas to be perceived individually, an additive mixture is produced when they consist of color lights (as in the case of the TV screen), a partitive mixture occurs when they are small pigmented color surfaces (as with the pointillist technique of painting), and a mixed syntheses occur – partially subtractive and partitive – if the small dots are made of transparent inks that in some zones overlap each other and in some others are separated on the background (as in the case of color printing).
Temporal Color Combinations
Phenomena of contrast appear whenever two or more colors are combined in a certain relation, but if this is a temporal combination, where the colors appear in a sequence, with certain durations and intervals, what is produced is a successive contrast or the phenomenon of post-image.
When the time span of visualization of a color that is followed by another is long enough, an adaptation to the first stimulus occurs, and, as a consequence, the second stimulus is affected by the successive color contrast.
When the frequency of appearance of two or more colors is fast enough to fall below the perceptive threshold (as in a flickering situation), an optical mixture of the colors involved in the sequence will be produced. It also happens here that two or more colors combined in these conditions give only one color as a result, the color that is the consequence of the optical mixture.
Color Selection as the First Step for Harmonic Color Combinations
If the specific chromatic relations among the combined colors are taken into account, the field of color harmony appears. There are a lot of proposals and theories about this. From a purely syntactical point of view, paying attention to the relations among the colors themselves and the quantity of colors combined (two or more colors), it is possible to mention, for instance, a combination of monochromatic colors, complementary colors, split complementaries, double complementaries, analogs, color triads or trichrome combinations, tetrachrome combinations, etc.
A Theory for Colors in Combination
This model for color combination was worked out along various years, and during its development their concepts, dimensions, and subvariables were changing to some extent. Previous formulations of this theory were published by Hård and Sivik in 1985 and 1994 [3, 4]. In some of these, for instance, the visual context in which the color combination appears is considered as a fourth and very important factor.
Semantic and Pragmatic Aspects in Color Combinations
It has been said at the beginning of this entry that the combination of colors is mainly a syntactical aspect. But since colors have a semantic weight, produce emotions, have meanings, are used as signals, indicate situations, propose behaviors, communicate messages, etc., and all this can vary according to the way in which colors are combined and according to the context, it is also possible to consider color combinations from a semantic point of view.
Here is a simple example. The three colors of the traffic lights (red, yellow, green) are a spatial and temporal syntactical combination, on one side. They make a triad of separated color lights, displayed in a circular shape, that appear with a spatially codified vertical arrangement: red at top, yellow in the middle, and green below. The temporal sequence is also regulated and codified: yellow comes after green and red comes after yellow. The step from red back to green is normally direct, without intermediation of yellow, and the same sequence is repeated again: green, yellow, and red; green, yellow, and red; and so on. The size of each color has also a specific relationship: the red circular light has a larger size than yellow and green. And the same happens with the time interval or duration in which each light is displayed: yellow appears for a brief instant, while red and green have longer durations. Now on, all these are purely syntactic aspects. Nothing has been said yet about what meaning this selection, arrangement, and sequence of combined colors conveys. By entering in the semantic domain, it is possible to talk about the codification of those three colors in that particular context of use: red means “stop,” and green means “go,” while yellow is a warning about the change of light from green to red that is coming soon and imply that the user has to take the necessary caution, either apply the brakes to stop the vehicle or speed up the march to make it through before the red light appears.
Thus, there are also semantic issues that are combined from a syntactical arrangement of colors and the context in which they are used and interpreted. The same red color used for the traffic lights may have very different meanings in other contexts: it may connote emotions such as passion, love, and rage; it may indicate something that is important to notice and deserves to stand out (a red typo in a context of black letters and words); it means expulsion from the field in the context of a football (soccer) match; it may also connote speed or status in a car (a red Ferrari), etc. Hence, it is the context (either the social, cultural, geographic, or temporal context in which the colors appear, as well as the relationship with other colors that are in the same context or situation) what endorses colors and color combinations with a certain sense or meaning.
Color combinations have been studied from the semantic point of view by various authors. Elda Cerrato points out the basic concepts behind the idea of color combination, discusses some color order systems and color harmony theories related to this (mainly Ostwald, Munsell, and Arnheim), and addresses the issue of how culture conditions harmonies, preferences, and aesthetical principles of color combinations .
Shigenobu Kobayashi, working at the Nippon Color and Design Research Institute, has devised a method to classify single colors or three-color combinations by their associated images [6, 7]. Through the analysis using the axes warm/cool, soft/hard, and clear/grayish as coordinates, this method, which was also extended and developed with some collaborators [8, 9], can plot climatic and cultural differences in color semantics. In 1997, Kobayashi and Iwamatsu extended the color combination research to be able to include five-color combinations , even when from the countless number of possible five-color combinations they chose to make the survey by selecting 20 pairs of contrasting combinations of five colors (40 color combinations in total). To justify that particular research, they point out that “a five-color combination makes it easier to gain a psychological understanding of scenic conditions and convey the sense of ambience than two- and three-color combinations.”
The book by Hideaki Chijiiwa, from the Musashino College of Art, at Musashino Art University, intends to be a manual for choosing color combinations for different purposes, taking into account meanings and mood . For practical applications in art, design, industry, or everyday life, it provides a guide for selecting two-, three-, and four-color combinations associated to adjectives such as striking, tranquil, exciting, natural, warm, cold, young, feminine, and surprising. As for the quantity of colors to be employed in a combination, the author advises to limit them to two or three. A warning is made when using four-color combinations that should be selected very carefully, while five-color combinations are directly discouraged. The book by Bride M. Whelan continues in the same venue .
Lars Sivik (working sometimes in collaboration with Anders Hård and Charles Taft) carried out research on the meanings of color combinations [13, 14, 15]. The descriptive model uses the Natural Color System as a basis, and the methods are aimed at studying the stability and variability of color-meaning associations across time and cultures. These studies “literally mapped the world of color with respect to how associations to various words systematically vary across different parts of the color world.” In the research published in 1989, Sivik selected 130 words by a semantic differential scaling method, and the subjects judged color images as “to how well the different word went with the color composition in question” . The main purpose was “to obtain a small number of variables that would be reasonably representative of all color describing variables.”
Other authors have also used the semantic differential method to study the meanings of color combinations, and more specifically their affective values, by applying this tool to two- and three-color harmonies [16, 17].
Colors, in general, and color combinations, in particular, can be considered as a system of signs; they certainly have syntactic aspects (which include both the elements and the combinatory), semantic aspects, and also pragmatic aspects that imply the use of these signs by the interpreters. In a previous publication, the author of this entry describes and illustrates various semiotic concepts with examples taken from color theory and provides an account of some of the advances of color theory within the framework of semiotic categories .
Some color theorists go even beyond these considerations, proposing that colors and color combinations can be taken as a language, for instance, Luckiesh in 1918 , Sanz in 1985 and 2009 [20, 21], Oberascher in 1993 , as well as Hård in the already mentioned article published in 1997 . However, this should be taken perhaps with certain caution. Human languages (for instance, verbal languages, English, Spanish, French, German, etc.) serve not only for communicational purposes but also for cognitive and modeling purposes; they allow to build categories, models, and theories about the world, in order to understand it, explain it, and make it meaningful for the human species. If it is possible to demonstrate that color combinations can have a similar status, then the color-language idea will be more than just a metaphor.
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