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The subtractive color process is the mixing of color with pigment; therefore, subtractive color is seen when light is absorbed or reflected by pigment.
Many visual communications professions depend on this method. It is particularly important for those practices that use paint and ink, such as any type of fine art, printing, or t-shirt creation.
To understand the differences between additive and subtractive color, you must first understand that one deals with light and the other deals with pigment, namely ink and paint. The other key difference is that in additive color, the combination of all colors creates white. Think about Newton’s experiments with prisms. Newton used prisms to separate white light into red, orange, yellow, green, blue, indigo and violet (ROY G BIV). Now think about the process in reverse. If you combine the colors of ROY G BIV, their confluence equates to white light. In simpler terms, adding all the colors of ROY G BIV or RGB together creates white, while removing all of them results in black. In subtractive color, white and black are produced by the opposite procedure. Think about a blank white canvas, or a brand-new piece of printer paper. With no pigments (paint or ink) applied to the canvas or paper, the result is a clean white surface. If all of the colors of ink or paint are mixed together, the color black is created.
In the image below, the additive color model RGB is compared to the subtractive color model CMYK (Cyan, Magenta, Yellow, Black). Notice how the overlapping colors for RGB create white and the corresponding overlays for CMYK create black.
EXAMPLE
Imagine you're painting, and you keep mixing more and more paints. Eventually, you get a sort of murky brown, and then black. This is subtractive color because even though you're adding color, you're really removing it and turning it to black.Remember that additive color does not involve working with pigments like paint or ink. Additive color involves light.
EXAMPLE
When designing for outputs like televisions, phones, or computer screens, adding more colors creates white instead of black.You might have noticed that the chart above has the letters CMYK, and that it doesn't have the primary colors that you're used to seeing (red, blue, and yellow). That is because subtractive color specification systems are used in the various professions that deal with printing. CMYK stands for the ink colors cyan, magenta, yellow, and black. These inks are the "four-color process" in the commercial printing industry. They are mixed on the printed page to produce the illusion of full color. As a subtractive color model, mixing full amounts of cyan, magenta, and yellow should result in black, which it does in theory. In practical application, it produces a very dark brown. To refer to the example of mixing paint, think about a plastic cup filled with water used to clean paintbrushes. The more paintbrushes rinsed in the cup, the darker the water gets until it's close to black.
Because black is not replicated purely by mixing cyan, magenta, and yellow, it must be specially formulated. This results in the extra color channel K, which represents black. A "K" is used to represent black because it refers to the key plate, which was the plate used in older methods of offset printing to align color registration and commonly used to print black ink. Using K to reference black also avoids the confusion of naming the color channel B, which would likely be misidentified to mean blue.
Working with black in the CMYK model requires some extra attention. Because different values of black can be created by mixing cyan, magenta, and yellow, it is often produced this way with the addition of the black color channel. While this is a valid technique to create different formulations of black, there are many times when black should not be produced by mixing other colors. An example of this can be seen in printing. The text in a newspaper or magazine should be produced using only the black color channel. Mixing all four colors results in too much ink being applied to very small areas that will likely bleed, smear, or seep through a piece of paper. When black is applied without the mixture of other colors, it is referred to as 100% black, true black, or pure black.
Unlike the RGB color model’s capability of producing over 16 million different colors, CMYK’s color range is more limited. Because CMYK creates colors by blending ink, the range is more limited with the total number of CMYK color possibilities restricted to a maximum of 16,000 potential outcomes. While 16,000 is still a large number, there are many printable colors that cannot be achieved through the four-color process. Certain color types like metallics can be achieved in print, but they require the formulation of a spot color, which in these terms refers to a printable color created through a specialized process.
Gamut is a term referring to the complete range of colors in a specific model. Color gamut is important as a design tool because it shows colors that are in and out of gamut. In-gamut colors can be replicated within a color model, whereas out-of-gamut selections cannot be produced. Color gamut is often used by designers to determine if RGB color selections will translate to CMYK outputs.
The image above shows the color gamut for LAB, RGB, and CMYK. LAB is a color model with a broader scope than RGB, encompassing the entire visual spectrum of the human eye. The area circled in white shows the in-gamut range for CMYK colors, whereas the black triangle depicts the scope of RGB colors.
Source: THIS TUTORIAL WAS AUTHORED BY MARIO E. HERNANDEZ FOR SOPHIA LEARNING. PLEASE SEE OUR TERMS OF USE.
