Foundations of Digital Image

04. Color

There are several color systems to identify and describe color. Computer systems can successfully simulate and represent color in various systems.


Hue Saturation Brightness/Value and Hue Saturation Lightness

The Munsell color system is a color space that specifies colors based on three color dimensions: hue, value (lightness), and chroma (color purity). It was created by Professor Albert H. Munsell in the first decade of the 20th century and adopted by the USDA as the official color system for soil research in the 1930s.

Due to its quite parametric character, it is widely used in digital systems as well as in scientific comparison systems.



Hue Value-Chroma



Color photograph


HSV value V


HSL lightness L


Red, Green and Blue

An RGB color space is any additive color space based on the RGB color model. A particular RGB color space is defined by the three chromaticities of red, green, and blue additive primaries and can produce any chromaticity that is in the triangle defined by those primary colors. The complete specification of an RGB color space also requires a white point chromaticity and a gamma correction curve.



Cyan, Magenta, Yellow, Black

The CMYK color model (process color, four color) is a subtractive color model used in color printing and is also used to describe the printing process itself. CMYK refers to the four inks used in some color printing: cyan, magenta, yellow, and key (black). Though it varies by print house, press operator, press manufacturer, and press run, ink is typically applied in the order of the abbreviation. When designing items to be printed, designers view the colors which they are choosing on an RGB color mode (their computer screen), and it is often difficult to visualize the way in which the color will turn out post printing because of this.




RGB in comparison to CMYK

RGB_and_CMYK_comparison    rgbcmyk

Hexadecimal representation

Hex Color Chart A

In color reproduction, including computer graphics and photography, the gamut, or color gamut, is a certain complete subset of colors. The most common usage refers to the subset of colors that can be accurately represented in a given circumstance, such as within a given color space or by a certain output device. Another usage of the gamut, less frequently used but not less correct, refers to the complete set of colors found within an image at a given time. In this context, digitizing a photograph, converting a digitized image to a different color space, or outputting it to a given medium using a certain output device generally alters its gamut, in the sense that some of the colors in the original are lost in the process.

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