About color models in Photoshop
A color mode determines the color model used to display and print images and color correction. Photoshop bases its color modes on established models for describing and reproducing color. Common models include HSB (hue, saturation, brightness); RGB color (red, green, blue); CMYK (cyan, magenta, yellow, black); and CIE L*a*b*. Photoshop also includes modes for specialized color output such as Indexed Color and Duotone. ImageReady uses RGB mode to work with images.
In addition to determining the number of colors that can be displayed in an image, color modes affect the number of channels and the file size of an image.
I will explain what it’s HSB, RGB, CMYK?
HSB model (Hue, Saturation, Brightness)
- Hue is the color reflected from or transmitted through an object. It is measured as a location on the standard color wheel, expressed as a degree between 0° and 360°. In common use, hue is identified by the name of the color such as red, orange, or green.
- Saturation, sometimes called chroma, is the strength or purity of the color. Saturation represents the amount of gray in proportion to the hue, measured as a percentage from 0% (gray) to 100% (fully saturated). On the standard color wheel, saturation increases from the center to the edge.
- Brightness is the relative lightness or darkness of the color, usually measured as a percentage from 0% (black) to 100% (white).
RGB model (Red Green Blue)
A large percentage of the visible spectrum can be represented by mixing red, green, and blue (RGB) colored light in various proportions and intensities. Where the colors overlap, they create cyan, magenta, yellow, and white.
Because the RGB colors combine to create white, they are also called additive colors. Adding all colors together creates white–that is, all visible wavelengths are transmitted back to the eye. Additive colors are used for lighting, video, and monitors. Your monitor, for example, creates color by emitting light through red, green, and blue phosphors.
CMYK model (Cyan, Magenta, Yellow,…)
The CMYK model is based on the light-absorbing quality of ink printed on paper. As white light strikes translucent inks, certain visible wavelengths are absorbed while others are reflected back to your eyes.
In theory, pure cyan (C), magenta (M), and yellow (Y) pigments should combine to absorb all light and produce black. For this reason these colors are called subtractive colors. Because all printing inks contain some impurities, these three inks actually produce a muddy brown and must be combined with black (K) ink to produce a true black. (K is used instead of B to avoid confusion with blue.) Combining these inks to reproduce color is called four-color process printing.
The subtractive (CMY) and additive (RGB) colors are complementary colors. Each pair of subtractive colors creates an additive color, and vice versa.
