CMYK Cyan Magenta Yellow Black CMYK and RGB

CMYK • Cyan • Magenta • Yellow • Black

CMYK and RGB Color

CMYK

CMYK

CMYK • CMYK (short for cyan, magenta, yellow, and key (Black), and often referred to as process color or four color) is a subtractive color model, used in color printing, also used to describe the printing process itself. • Such a model is called subtractive because inks “subtract” brightness from white.

RGB • Red • Green • Blue

RGB

RGB • The RGB color model is an additive model in • which red, green, and blue (often used in additive light models) are combined in various ways to reproduce other colors. The name of the model and the abbreviation ‘RGB’ come from the three primary colors, red, green, and blue and the technological development of cathode ray tubes which could display color instead of a monochrome phosphoresence (including grey scaling) such as black and white film and television imaging.

CMYK vs RGB • CMYK = printing • RGB = on screen

CMYK vs RGB • In additive color models such as RGB, white is • • the “additive” combination of all primary colored lights, while black is the absence of light. In the CMYK model, it is just the opposite: white is the natural color of the paper or other background, while black results from a full combination of colored inks. To save money on ink, and to produce deeper black tones, unsaturated and dark colors are produced by substituting black ink for the combination of cyan, magenta and yellow.

CMYK vs RGB • Comparisons between RGB displays and CMYK prints can • • • be difficult, since the color reproduction technologies and properties are so different. A laser or ink-jet printer prints in dots per inch (dpi) which is very different from a computer screen, which displays graphics in pixels per inch (ppi). A computer screen mixes shades of red, green, and blue to create color pictures. A CMYK printer must compete with the many shades of RGB with only one shade of each of cyan, magenta and yellow, which it will mix using dithering, halftoning or some other optical technique; this dithering produces a lower level of detail than the printer's dpi suggests.

Color spaces • Color is typically organized in a hierarchal fashion, based on how colors are mixed. A color space helps to define how the colors are mixed, based on the medium in which the colors are used. There are two different kinds of color spaces:

Subtractive Additive

Color • Color is the response of the eye to differing wavelengths of radiation within the visible spectrum. The visible spectrum is what we perceive as light. It is the part of the electromagnetic spectrum that we can see. The typical human eye will respond to wavelengths between 400 -700 nanometers (nm), with red being at one end (700 nm), violet at the other (400 nm) and every other color in between these two.

Color • There are many different kinds of color systems, and many different theories on color. We will get into that kind of detail in a later column. For now we will focus on the basics, using a color wheel for illustration purposes. There are three main components of color: • Hue: Where the color is positioned on the color wheel. Terms such • • as red, blue-green, and mauve all define the hue of a given color. Value: The general lightness or darkness of a color. In general, how close to black or white a given color is. Saturation: The intensity, or level of chroma, of a color. The more gray a color has in it, the less chroma it has.

Hue, Value and Saturation

Color Harmonies Analagous Complimentary Triadic

Color Harmonies • Color harmonies serve to describe the relationships certain colors have to one another, and how they can be combined to create a palette of color. • Complementary: A complementary relationship is a harmony of two colors • • on the opposite side of the color wheel. When complementary colors are placed side-by-side they tend to enhance the intensity (chroma) of each other, and when they are blended together they tend to decrease the intensity of each other. Analogous: An analogous relationship is a harmony of colors whose hues are adjacent to one another on the color wheel. Analogous colors tend to be families of colors such as blues (blue, blue-violet, blue-green) and yellows (yellow, yellow-orange, yellow-green). Triadic: A triadic relationship is a harmony of three colors equidistant from one another on the color wheel. Primary colors and secondary colors are examples of color triads.