We all own colour TVs, cameras and mobile phones which all have some great colour displays. Those same colour photos that we click on our cameras are then re-produced in colour with the help of a printer. While we all enjoy looking at life in colour, do we really know how this colour is produced? As you continue to read this article, by the end of it, you would know exactly how colour is reproduced on all our gadgets as well as paper after printing.
RGB colour model:
The RGB colour model is an additive colour model in which red, green, and blue light is added together in a variety of ways to reproduce a broad array of colours. The name of the RGB colour model comes from the initials of the three additive primary colors, red, green, and blue.
The main purpose of the RGB colour model is for the sensing, representation, and display of images in electronic systems, such as televisions and computers, though it has also been used in conventional photography.
CMYK colour model:
The CMYK colour model is a subtractive colour model, used in colour printing, and is also used to describe the printing process itself.
CMYK refers to the four inks used in colour printing: cyan, magenta, yellow, and key (black).
The CMYK model works by partially or entirely masking colours on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected. Such a model is called subtractive because the inks remove the brightness from white.
CMYK vs RGB:
Comparisons between RGB displays and CMYK prints can be difficult as the colour reproduction technologies and properties are so different.
A computer monitor mixes shades of red, green, and blue to create colour pictures.
A CMYK printer instead uses light-absorbing cyan, magenta and yellow inks, whose colours are mixed using dithering, halftoning, or some other optical techniques.
CMYK and RGB devices:
While the CMYK colour model is restricted to printing devices, typical RGB input devices include colour TVs and video cameras, image scanners, and digital cameras. Typical RGB output devices are TV sets of various technologies (CRT, LCD, plasma, etc.), computer and mobile phone displays, video projectors, multicolor LED displays.
RGB, CMYK and how its displayed:
One of the most common applications of the RGB colour model is the display of colours on a cathode ray tube (CRT), liquid crystal display (LCD), plasma display, or LED display such as a television, a computer’s monitor, or a large scale screen. Each pixel on the screen is built by driving three separated RGB light sources. At the common viewing distance, the separate sources are indistinguishable, which tricks the eye to see a given solid colour.
CMYK or process colour printing is contrasted with spot colour printing, in which specific coloured inks are used to produce the colours appearing on paper. Some printing presses are capable of printing with both four-colour process inks and additional spot colour inks at the same time. High-quality printed materials, such as marketing brochures and books, may include photographs requiring process-colour printing, other graphic effects requiring spot colours (such as metallic inks), and finishes such as varnish, which enhances the glossy appearance of the printed piece.
Now that you understand the RGB and CMYK colour models better, here’s a little additional research you can do on the given topic.
- Remember finger painting? By mixing three primary colours, any color could be generated.
Swirling all colors together resulted in a muddy brown. Revisit your art class and see what colour is produced when primary colours are mixed together.
- Find out all that you can about spot colour printing and offset printing.
- Apart from the RGB and CMYK colour model, can you think of another colour model?
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