What are subtractive colors?
Subtractive colors refer to colors that are created by absorbing or subtracting wavelengths of light. Unlike additive colors that emit light, subtractive colors work by selectively absorbing certain wavelengths of light and reflecting the rest. This absorption and reflection process creates the visual perception of color.
The primary subtractive colors are cyan, magenta, and yellow. When these colors are combined or overlapped, they create new subtractive colors:
| Cyan + Magenta | Blue |
| Cyan + Yellow | Green |
| Magenta + Yellow | Red |
| Cyan + Magenta + Yellow | Black |
The absorption and reflection of light wavelengths work as follows:
– Cyan pigments absorb red light and reflect blue and green light.
– Magenta pigments absorb green light and reflect blue and red light.
– Yellow pigments absorb blue light and reflect red and green light.
When two subtractive colors overlap, the absorbed wavelengths combine. For example, magenta absorbs green light while yellow absorbs blue light. When combined, magenta and yellow together absorb both green and blue, leaving only red light reflected. This creates the perception of red color.
The more subtractive colors that are combined, the more wavelengths are absorbed, eventually leading to black which absorbs all visible wavelengths of light.
Subtractive color models
There are two major subtractive color models that are widely used – CMY and RYB:
CMY model
The CMY model uses the primary colors cyan, magenta, and yellow. This is the most common model used in color printing. Cyan, magenta, and yellow pigments are applied to a white surface or paper. By absorbing wavelengths of light, they create a full spectrum of colors:
| Cyan | Absorbs red light |
| Magenta | Absorbs green light |
| Yellow | Absorbs blue light |
When combined together, cyan, magenta, and yellow absorb most visible light, creating the color black:
| Cyan + Magenta + Yellow | Black |
The CMY model is used for color printing, both in full color process printing and in desktop color printers and copiers. The complementary colors of cyan, magenta and yellow are red, green and blue – the three additive primary colors.
RYB model
The RYB model uses the primary colors red, yellow, and blue. This model was traditionally used by artists for mixing paint colors. The primary colors red, yellow and blue can be combined to create a full spectrum of hues:
| Red | Absorbs cyan light |
| Yellow | Absorbs blue light |
| Blue | Absorbs yellow light |
When RYB colors overlap, they create the subtractive secondaries:
| Red + Yellow | Orange |
| Red + Blue | Violet |
| Yellow + Blue | Green |
All three primaries together produce a dark gray or black. The RYB model originated from the limited pigment colors that were available to artists in the 18th and 19th centuries. Modern color theory now utilizes the more accurate CMY model.
Practical applications of subtractive color
Subtractive color has many practical applications, most notably in the printing and painting industries:
Color printing
Cyan, magenta, yellow and black (CMYK) inks are used in color printing to absorb select wavelengths and reproduce a wide array of colors by layering combinations of these inks on paper.
Cyan, magenta and yellow are the primary subtractive colors, while black (K) ink is added for better contrast and to produce true black color. Color images and documents are separated into these 4 channels for printing.
Paint and pigments
Paints contain colored pigments that act as subtractive colors by absorbing certain wavelengths and selectively reflecting others. For example, vermilion paint absorbs green and blue light and reflects only red wavelengths, creating a vivid red color.
Early painters used subtractive RYB primary colors to mix paints. Modern acrylic and oil paints use more sophisticated cyan, magenta and yellow pigments.
Dyes and fabrics
Fabric dyes work on the same subtractive principle. As the dye molecules are absorbed into fabric fibers, they filter specific wavelengths of light and subtract colors from white light shining on them.
Different classes of dyes are used industrially to color fabric, like reactive dyes, vat dyes and sulfur dyes. These are capable of bonding with different textile fibers.
Color photography and film
Traditional color film and photography rely on subtractive CMY color modes. Layers of cyan, magenta and yellow light-sensitive emulsions are coated onto the film. When exposed to light, they produce cyan, magenta and yellow dyes in proportion to the amount of red, blue and green light entering the camera.
Digital sensors have replaced film in most photography. However, the principles of subtractive color continue to be used in image processing algorithms.
Inkjet printers
Consumer inkjet printers mix cyan, magenta, yellow and black inks to reproduce color images on paper. The relative proportions of the inks are controlled digitally to filter select light wavelengths and approximate the color gamut of an image.
Higher end inkjets may add lighter cyan and magenta inks to expand the printable color gamut. White ink is also sometimes added as a base layer to improve the vibrancy of colors on non-white media.
Color copiers
Color laser and inkjet copiers commonly employ four color toners – CMYK – to replicate document originals. During the scanning stage, red, green and blue light is used to capture color information. This is then converted to appropriate mixtures of the cyan, magenta, yellow and black toners to reconstruct the colors on paper.
Key characteristics of subtractive color
Some key characteristics of subtractive color systems are:
– Reliance on dyes, pigments or colorants to absorb/subtract wavelengths of light
– CMY and RYB are common subtractive primary color sets
– Combining subtractive primaries creates secondary or tertiary colors
– Increasing overlap absorbs more wavelengths, eventually creating black
– Used in printing, paints, dyes, inks, photography and other imaging systems
– Provides a controllable way of producing color hues and tones by subtracting wavelengths
– Relies on reflected light from colored surfaces entering the eye to create color perception
– Used in additive (red, green, blue) systems also through color transforms and color management
– Replicates color through precise control of cyan, magenta, yellow and black in proportional amounts
Differences between additive and subtractive color
Additive and subtractive are complementary color systems. Here are some key differences:
| Additive | Subtractive |
| Colors produced by combining red, green, blue light | Colors produced by selectively absorbing wavelengths with pigments/dyes |
| Emissive – emits light | Reflective – reflects some light, absorbs other wavelengths |
| Used in TV, digital displays, projectors | Used in printing, painting, dyeing |
| Combines light to create new hues | Subtracts wavelengths from white light |
| RGB color model | CMY/RYB color models |
While different in approach, additive and subtractive systems aim to recreate the full spectrum of visible color hues, tones and shades. Advancements in color science now allow converting between the two for consistent color reproduction across different media.
Conclusion
Subtractive color forms the basis of color creation in fields like printing, textile dyeing, painting and photography. It provides a controllable way of producing colors by selectively absorbing wavelengths of light with pigments, dyes and colorants. The subtractive primaries are cyan, magenta and yellow, which can be overlapped to produce secondary colors. Increasing combinations eventually absorb all wavelengths, resulting in black.
Subtractive color follows physical principles opposite to additive color. However, both systems aim to accurately reproduce visual color. Modern color management utilizes color transforms and profiles to transition between the two models, ensuring consistent color between displays, prints, films and other media. This allows us to enjoy vibrant and accurate color reproduction across the myriad devices and surfaces we use in our daily lives.
