Color is a fascinating aspect of the world we live in. It surrounds us everywhere, every moment, influencing our moods, our decisions and how we interpret our surroundings. But have you ever stopped to think about the nature of color and how we perceive it? Fundamentally, there are two main ways in which we experience color: through color light and color pigment. Both phenomena are essential to our perception of the world, but operate on very different principles.
What is Color Light?
White light, such as sunlight, is composed of a combination of many colors. When this light passes through a prism, it breaks down into its constituent colors, creating a spectrum of colors: the familiar rainbow from red to violet. This brings us to the concept of light, or additive, color.
The additive color system is based on the mixing of light of different colors. The primary colors in this system are red, green and blue(RGB). When we combine these lights in different proportions, we can create almost any color visible to the human eye.
If you mix red light and green light, you get yellow light; mixing green light and blue light, you get cyan; and mixing red light and blue light, you get magenta. And when you combine all three lights in equal proportions, you get white light. The screens of our electronic devices, such as televisions and smartphones, use this principle to produce a wide range of colors.
Additive Color System: Characteristics
The RGB (Red, Green, Blue) system is one of the most common color systems and is fundamental in the representation of images in electronic devices. We are going to describe all the characteristics of this model;
- Additive model: RGB is an additive color system. This means that colors are created by adding light. The more color you add, the closer the result will be to white light.
- Primary colors: The primary colors in this system are Red, Green and Blue. From the combination of these three colors, it is possible to generate a wide range of colors.
- Creation of secondary colors: By combining two of the primary colors at their maximum intensity, the secondary colors of the model are obtained: Red Green = Yellow / Red Blue = Magenta / Green Blue = Cyan
- The absence of all colors (0 intensity in red, green and blue) results in black.
- Maximum presence of all colors (maximum intensity in red, green and blue) results in white.
- Use in electronic devices: The RGB system is the standard for displaying images on electronic devices, such as monitors, televisions, smartphones and tablets. This is because these devices generate images through the emission of light.
- Digital representation: In the digital realm, each color (R, G, B) is often represented by a value ranging from 0 to 255. For example, pure red would be represented as (255, 0, 0), while white would be (255, 255, 255).
- Applications in design and photography: Since most devices and displays use RGB, graphic design, video editing and digital photography tend to work predominantly in this color space.
- Conversion to other color spaces: It is possible to convert images from the RGB color space to other spaces, such as CMYK (used in printing). However, not all colors in RGB can be perfectly represented in CMYK and vice versa, which can lead to challenges in color reproduction.
- Perception: Human color perception is closer to the RGB model than to many other models because our eyes have receptor cells (cones) that are sensitive primarily to wavelengths corresponding to red, green and blue.
- Limitations: Although RGB can represent a wide range of colors, it does not encompass all colors visible to the human eye. There are colors, especially at the extremes of the visible spectrum, that cannot be accurately represented in RGB.
What is Pigment Color?
On the other hand, pigment color, also known as subtractive color, refers to how we perceive color from the pigments or dyes present in objects such as paints, inks and other materials. Unlike light color, where light is emitted directly, pigments work by absorbing certain wavelengths of light and reflecting others.
The primary colors in the subtractive system are cyan, magenta and yellow (CMY). By mixing these colors in different proportions, we can create a variety of other colors. Interestingly, if you mix cyan and magenta, you get blue; mixing cyan and yellow, you get green; and mixing magenta and yellow, you get red.
However, in practice, mixing these pigments does not produce a perfect black due to impurities in the dyes and pigments. That is why a fourth color, black (K for “key”), is used in printing, giving rise to the CMYK model used in color printing.
CMYK Model: Characteristics
The CMYK system (Cyan, Magenta, Yellow, Key/Black) is another essential color model, especially in the printing world. Here are the characteristics of this model:
- Subtractive Model: Unlike RGB which is additive, CMYK is a subtractive system. This means that colors are created by absorbing light. On a white paper, the absence of ink reflects light and is perceived as white. As inks are added, certain wavelengths are absorbed and others are reflected, creating perceptions of different colors.
- Primary colors: In this system, the primary colors are Cyan, Magenta and Yellow. These colors, in theory, when combined in equal proportions, should produce black, but due to imperfections in the actual inks, instead produce a dark brown.
- Black (Key): Due to the aforementioned imperfection in the inks, a fourth color, black, is added to produce true blacks and to increase the depth and definition of the printed image.
- Main use in Printing: The CMYK system is the standard in the printing industry, whether for magazines, posters, brochures, books, among others.
- Digital representation: Like RGB, in the digital world each color (C, M, Y, K) is usually represented with a percentage value, being 0% the absence of that color and 100% the maximum saturation of it.
- Conversion from RGB: Images originally created in RGB (such as digital photos) must be converted to CMYK for printing. This conversion can lead to color shifts, as the color space of RGB is different from CMYK.
- Limitations of the color space: Like RGB, the CMYK system has its limitations. There are colors in RGB that cannot be represented exactly in CMYK and vice versa.
- Design applications: Graphic designers working on projects intended for print often work in the CMYK color space to ensure that the colors they see on screen are as close as possible to those that will appear in print.
- Color Depth: Often in high quality printing, variants of CMYK are used with additional inks to achieve specific colors or to increase the range of printable colors.
- Variability with inks: The final appearance of a CMYK printed product can vary depending on the type and quality of ink, the paper used and the printing press.
Interaction and Perception
The reason we see colors in objects around us is because of how they interact with light. A tomato is perceived as red because it absorbs all wavelengths of white light except red, which it reflects back to our eyes.
Color perception is also influenced by the biology of our eyes. The cones, color-sensitive cells in our retina, are most sensitive to wavelengths corresponding to red, green and blue. This is another reason why the RGB system is so prevalent in display technology.
Applications and Significance
Both light color and pigment color have practical applications in our daily lives. The arts, advertising, technology and science use a deep understanding of these principles to create images, products and experiments that connect with our perception and emotion.
In addition to its practical function, color has deep cultural and psychological significance. Different colors evoke different emotions and responses in people. Colors also have symbolic meanings in different cultures, and the color palette an artist or designer chooses can convey a specific message or evoke a particular emotion.