Color Spaces – RGB, CMYK, LAB

RGB Color Space

We all know it by the name its acronym of Red, Green and Blue.

RGB is the most common color model in use today.

All the digital cameras, scanners actually acquire data on principles based on the principles of RGB. Every monitor in the world works with RGB. Most of all, the web is entirely RGB-based. There is no CMYK in the web so it’s a different world from printing.

In RGB, Each channel describes the intensity of light of a given color. We can build colors by adding different sources of Red, Green and Blue color in different percentages in 8-bit representation. Each channel has a variation range between 0 and 255. If you wonder why such a strange number, not 100 or 1000 is it depends on the fact that we are working with an 8-bit number which only has 256 possible values that’s 2 to the power of 8 basically, so if you count the 0 as well that’s the allowed range.

The components should be thought as illuminants. 0 means “no light”, 255 means “maximum light”.  Behind every pixel on the monitor there are 3 sub pixels Red, Green and Blue, it’s like tiny little lamps that go on together at different intensities. 

RGB is a color model.When we actually say which color make up the red green and blue component we obtain a color space. RGB is the most intuitive color space.

CMYK Color Space

CMYK is instead the acronym of Cyan, Magenta, Yellow and Key many think that the K comes from the last letter of black but that’s not true because black is the key plate on which every other plate is put to register. so CMYK as you know is a traditional printing color space. It is the basis of traditional offset printing.

CMYK provides total control on printed output. Its small gamut allows very fine adjustments of color. It is the most powerful color space to handle shadows. But its small gamut makes it impossible to obtain bright and brilliant colors. It is quite a difficult colorspace to work with. It’s rather hard to find someone who is really knowledgeable about CMYK today.

LAB Color Space

L is the acronym of lightness which basically means how light or dark is a color whereas the a and B mean nothing in particular they are just letters.LAB is the most abstract color space of the three with completely different rules from both RGB and CMYK. LAB is considered difficult to color space but it’s also very powerful. It contains colors that we can’t see and also colors that can’t be imagined.

The L channel describes how dark or light a color is. 

L varies between 0 and 100,

Where 0 means total darkness and 100 maximum light.

The a and b channels describe the color, unrelated to luminosity.

a describes whether a color is biased towards green or magenta,

b describes whether a color is biased towards blue or yellow.

the a and b channels can be negative. They can vary between -128 and 127.

LAB has an enormous gamut! When compared to sRGB/Adobe RGB, LAB is a very huge color space. It is the color space of choice to make big changes in color. Its separation of luminosity and color opens the door to new techniques. 

It is a more perceptually uniform than other color spaces, It can be used to isolate colors more efficiently that any other color space. It also can enhance color micro variations. But also note that it is a huge color space and can be difficult and frustrating to manage and can break apart the image if not handled correctly.