additive color models essentially differ in two types: RGB and CMYK. Here we will look into the RGB color model, which is based on a three color palette made up of red, green, and blue. This model underlies the operation of digital displays such as set and computer monitors. The saturation of each of these colors is represented as a like decimal value ranging from 0-255.
Unlike RGB, CMYK, or ‘Process Colors’, is a subtractive color model. It's commonly used in printing, which differs significantly due to the way colors are created through the absorption of light. Instead of adding color, CMYK employs the overlapping of inks to create secondary colors. This is represented by a percentage calculated from 0% to 100%.
RGB (Red, Green, Blue) Color Model
The RGB color model is based on the human cone cells that take in light. Its power lies in the premise that through the strategic combination of red, green, and blue, any color can be created. The three colors are basically combined to create more colors.
Component colors in the RGB model each have 256 possible shades or values. When combined, they have a total of 16.78 million possibilities. The lowest value (0,0,0) is black and the highest (255,255,255) white. This rich palette of shades allows for easy matching to real-world colors, making RGB excellent for digital displays.
RGB in Light Emission
RGB color model begins with light. Light is emitted by the RGB elements, which can cover the entire spectrum of colors. For example, green pixels contain RGB which emits only green light.
In contrast, subtractive color models, such as CMYK, absorb all colors but those they reflect. This is why different elements in CMYK systems like ink, paints, and dyes can’t produce the same shades of color in RGB, especially vibrant and neon colors.
RGB in Image Editing
The RGB color model is widely implemented in image editing software. Programs like Adobe Photoshop, GIMP, and Paint Shop Pro often have RGB as their prevalent color space. It also forms the basis of .jpeg, .png, .bmp, and most other digital image formats.
When editing an image, it's important to realize that each color channel corresponds to strands of the three cones on the eye's retina. In the RGB color model, white is represented by full red, green, and blue and black as the complete absence of these three colors.
CMYK (Cyan, Magenta, Yellow, Black) Color Model
The CMYK color model doesn’t use white, it defines black by using all the colors. Black, therefore, is not the absence of light, but the presence of all inks. The model is subtractive as colors become more vibrant as more colors are added which darkens the white background.
As mentioned earlier, CMYK uses percentages to represent the saturation of color, with 0% being no color (white) and 100% the most vibrant color. This is done to facilitate easy control of colors in printing. It contrasts RGB's 0-255 scale where higher numbers mean more vibrant colors.
CMYK in Printed Color
CMYK or four-color process, originally used to color printings, drives the bulk of color printing. It does this by combining three primary colors (cyan, magenta, and yellow) and black to produce a whole range of colors.
Some nuanced factors tie the CMYK model to printed color. For example, printer ink printed on paper must have a base color. This is white - from the paper stock. So, while the paper has an infinite range of whites, once it's printed upon, the ink absorbs light, cutting out the paper's white, giving it color.
CMYK in Design Software
Many graphic design software like Adobe Illustrator. CorelDRAW, and Inkscape apply the CMYK color model. This is because, in the early years of computing, when printers were primarily used, most graphic design software modeled itself to fit the subtractive color theory as was dominant in the industry.
Despite RGB emergence with the advent of digital displays, many legacy designs, logos, and marketing materials still use CMYK. Therefore, knowledge of the CMYK model is vital, even with RGB dominance in digital displays. In fact, your printer will convert your RGB images to CMYK ready for printing.
To conclude, RGB and CMYK color models differ significantly from each other. They have distinct uses, that is, RGB is ideal for digital displays while CMYK excels in print. Understanding each model will help you navigate between digital and print world effectively and create the best results.