Color Models in Images

Presented by Krsna Chandarana 

• Color Image
• Color Models 
• Types of Model 
• Color Model used in Print

INDEX

Color  Model

A color model is a system that helps us to define and describe colors through numerical values. There are many types of color models that use different mathematical systems to represent colors, although most color models typically use a combination of three or four values or color components.

Types

The RGB model is used when working with digital screen based designs, such as those viewed on a computer screen or phone display. In the RGB color model, a value between 0 and 255 is assigned to each of the primary colors, Red, Green and Blue, where 0 is dark and 255 is bright. By listing the three values for the red, green and blue phosphors, you can specify the exact color that will be mixed.The RGB color model is an additive color system, which means colors get lighter when mixed.

RGB

As each component of light is mixed in, the combination becomes a new color. Red, green and blue are the three additive primaries. You can create any color within the constraint of the device using different combinations of the additive primaries. When you mix all three together in balanced amounts, you get white.

Television screens and computer monitors create color by turning on the red, green and blue primaries within each pixel. By changing each of the red, green, and blue primaries within a pixel to a different brightness, the monitor creates unique colors.

The CMYK color model describes colors based on their percentage of Cyan, Magenta, Yellow and Black. Many computer printers and traditional "four-color" printing presses use the CMYK model. In the CMYK model, by mixing cyan, magenta, yellow and black inks or paints, you can create nearly any color desired.In theory, you can mix any reflective color by mixing a combination of cyan, magenta and yellow alone.

CMYK

In the real world, however, the inks that printers use are not perfect. This becomes most obvious when you mix all three equally to make black. The color that results is muddy brown because the primaries overlap and don’t perfectly subtract light when mixed.

CMYK is a subtractive color model, which means colors get darker when mixed. Each of the mixed paints or inks absorbs different components of the light. If the right combination of paints is mixed together, all of the components of light are absorbed and the result is a near black.

The HSL model is very similar to the RGB color model. In fact, when they're expressed mathematically, they're identical. The difference lies in how colors are expressed numerically.

The hue determines which basic color it is. Red, green, blue, yellow, orange, etc. are different hues. Saturation and luminance tell more about the variations of these basic colors. Saturation is the vividness (or "purity") of the color, i.e., how much of the color's complement is mixed in. Finally, lightness refers to the "whiteness" of the color. It may also be termed "brightness," "value" or "intensity."

HSL

YIQ is the most widely colour model used in Television broadcasting. Y stands for luminance part and IQ stands for chrominance part. In the black and white television, only the luminance part (Y) was broadcast. The y value is similar to the grayscale part. The colour information is represented by the IQ part.

YIQ

• https://www.pantone.com/articles/color-fundamentals/color-models-explained#:~:text=A%20color%20model%20is%20a%20system%20used%20to%20describe%20a,Yellow%20and%20Black%20(CMYK).
• https://www.geeksforgeeks.org/differences-between-rgb-and-cmyk-color-schemes/
• https://www.geeksforgeeks.org/difference-between-rgb-cmyk-hsv-and-yiq-color-models/
• https://acsweb.ucsd.edu/~ncn003/CSE3/Lab2/ColorModels.htm
• https://www.easytechjunkie.com/what-is-a-color-image.htm
• https://www-i6.informatik.rwth-aachen.de/web/Misc/Coding/365/li/material/notes/Chap3/Chap3.3/Chap3.3.html#:~:text=Two%20common%20color%20models%20in,YIQ%20uses%20similar%20idea.

Bibliography

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