Color theory


Color theory.


Introduction to color.


More and more people are discovering the digital imaging market. Digital cameras, color printers and scanners are becoming more and more cheaper and thus become available to an increasing number of users. With this revolution in the use of color appeared, and the need to understand what is a digital color and understand its features. Studies show that the end users are baffled by the complex behavior of digital color and often complain that "color print does not look like the one on the monitor." Despite remarkable progress in the technology of color reproduction is clear that few people understand the theory of digital color. Due to the inability to understand the new technologies of color the customer may be disappointed in the product or requirements of the excessive demands.

Company Spittin 'Image Software introduces a new simple inventions designed to explain to people the principles of digital color. This invention was patented in the US under the name COLORCUBE. It is an image of a physical model of how color is stored, processed and reproduced in digital devices.



COLORCUBE - a three-dimensional model, which can be used to learn or to teach the theory of digital color. This is an elegant representation of colors eliminates the gap between additive and subtractive color scheme, and also defines the methods by which colors are stored, processed and reproduced in computer technology.


As the human eye sees color.


In the human eye contains two types of receptors: rods and cones. Coli react grayscale using cones and brain can perceive the color spectrum. There are three types of cones: the first to respond to red-orange color, the second - on the green, and the third - on the blue-violet.



When only one type driven cone brain sees only one corresponding color. Thus, if stimulated our "green" cones - we see "green" color. If the red-orange - "red". If at the same time stimulate the green and red-orange cones, we see yellow. The eye can not distinguish real amber from some combination of red and green. The same applies to our perception of colors such as cyan, magenta, and the other between the spectral colors. Because of this physiological properties of our eyes, we can his "cheat" by providing a full range of visible colors by mixing instructions only three: red, green, and blue.


Determination of the primary colors.


Expanding any color using a prism it is possible to determine the components of red, green and blue (basic additive color), or cyan, yellow and magenta (subtractive basic colors). This simple but illustrative method allows to determine the true primary colors. The more accurately we know what colors are basic, the more secondary colors with their help we can reproduce.


Additive and subtractive color.


TV, cameras, scanners, monitors, computers based on the additive color system (RGB), where red (R), green (G) and blue (B) in combination produce white. Offset printing, digital printing, ink, plastic, cloth and the photo based on the subtractive color system (CMY / CMYK), wherein the mixture of cyan (C), magenta (M) and yellow (Y) created black (K). COLORCUBE uniqueness is that it both systems are combined in a single model. To switch from the RGB in CMYK, just enough to rotate the cube.


RGB and CMY axis placed in the same space of reference colors. View from the outside.


Color models.


With each new advance in the theory of color there is a new model, with which describes this new theory. Unfortunately, the adherents of the old color models rarely when they pay attention to the new model. For example, now a popular color wheel is not much different in appearance and work on what was presented by Sir Isaac Newton. Artists, based on the circle, still incorrectly believe the primary colors red, yellow and blue in spite of the fact that technologies such as offset printing and photography, which is already more than a hundred years, based on a three-dimensional color system where the primary colors are cyan, magenta and yellow. Among other models used by specialists in various sectors are: Hue / Saturation / Value (HSV), maps CMYK, as RGB, color scheme Pantone, the system CIE, DIN and standard color card spectral glow.

Computers and other digital devices define color based on the color of the new model, which is called COLORCUBE. It covers the area of digital color representation.


Storing images on a computer.


All digital devices work with color store, process, and reproduce color and color images using the values of RGB. In order to maintain a digital image, it first needs to be divided into a grid of small pixels (dots). Each pixel is measured by the number it red, green and blue colors. Then the entire image is recorded pixel by pixel. For image storage area of 3 square inches with a resolution of 150 dpi is required 202.500 pixels or 607,500 bytes. Often a theoretical model describing the principle of storage of flowers in the computer are in the form of a cube. This method has proven himself, allowing you to easily switch between different color models, including color circle diagram CIE, scheme HSV, scope Munsel, system Pantone, color standards and DIN color map of spectral glow.

COLORCUBE fundamental difference from all other models is that describes the color cube in the color space based on input parameters (number of primary color pigment used for creating mixed color). Others are based on the measurement model output parameters (i.e. on the appearance of the resulting color). The color scheme is based on the input parameters, greatly facilitates the solution of problems with the names of colors, from the playback output, calibration, processing and conversion to other color schemes.



Presentation of colors.


Opportunity to present all the existing colors in the form of three-dimensional color gamut and see their relationship with each other is a huge advantage when working with color. Although there are already a number of computer models that show theoretically colors, model COLORCUBE first of its kind physical model, in which all visible interior colors. The human eye is capable of seeing more than 16 million colors. COLORCUBE key property is that first defined the outer points of the cube, and then determines the colors and shades between these key points. Thus, defining the extreme boundaries of colors, we get to see and also intermediate colors. By specifying the total number of colors required, we can generate any density cubes. For example, COLORCUBE that defines all colors will be reproducible in each face 256 cubes, i.e. the cubes consist of 16,777,216.


Mixing colors.


Each color element in COLORCUBE has a unique numeric identifier, indicating what proportion of the original values were used to reproduce the color. Each element also has its unique location inside the cube. In this way a connection between the position information and information about how you mix the colors for this item. If given information about the mixing of colors, we can always figure out where the cube is given element. If given the location of the item, we can calculate in what proportion it is necessary to mix the primary colors to get the color of the item. Using this property COLORCUBE we do not need no longer wonder about the color names, descriptions, and mixing parameters. Now we can be pretty sure that we have defined digital color can always play in this scheme and that it will be the same color.


The choice of color.


The unique three-dimensional arrangement of colors in the model COLORCUBE perfect for color selection tool. With the help of the cube you can easily define additional colors, harmonious combinations to choose warm and cool colors, find unsaturated colors, hues, colors with the same values. It becomes clear that all the relationships between the colors are mathematical in nature, and these relationships can be modeled using simple mathematics in Cartesian coordinates XYZ.



Color manipulation.


For manipulation with flowers in the colors need to define a set of mathematical rules by which will change color. Mathematics color color breaks into its constituent primary colors, and then provides them with mathematical operations. As a result of mixing formulas are derived for any new color selected with COLORCUBE. For example, in order to predict the result of mixing two colors, spread each color into its primary colors. Then, fold the same basic color. The result is a position for which can be found in COLORCUBE resulting color. The same logic applies to the subtraction of colors (the subtraction of one color from another), as well as more complex operations such as adjusting the brightness, contrast and saturation.



Defining colors and calibration.


Problems arising from the calibration and determination of colors, due to the fact that all of these systems use different ranges of visible colors. In order to effectively determine the color matching between different color systems, you need to perform complex mathematical calculations. If these calculations do not sufficiently accurate, the colors of the final image will not match the original. Currently, to determine the correct color matching spectral measurements produced by each device involved in the process, while under the same illumination conditions. After that, the colors are converted to a single field of CIE.

In such popular programs like Corel Photo Paint, and Hewlett Packard Scanning funds are available with two-dimensional interface color calibration. These interfaces are difficult to use, does not give complete information and require a deep knowledge about the color. If the three-dimensional model of color will be recognized and will be used in the interface, it will be a significant step in their improvement. In three-dimensional space is easier to display different color systems and their compliance as well as the entire set of theoretically visible colors.


Wavelength of light.