Yellow is a bright, warm color that is often associated with happiness, optimism, and energy. In art and design, yellow can create feelings of joy and cheerfulness. But where does the color yellow come from? What pigments or combinations of colors make yellow?
Primary Colors
In painting, primary colors are colors that can’t be mixed from other colors. The primary colors are red, blue, and yellow. Secondary colors are made by mixing two primary colors. For example, mixing red and yellow makes orange. Tertiary colors are made by mixing a primary color with a secondary color next to it on the color wheel. Mixing yellow and orange makes yellow-orange.
So yellow is considered a primary color in painting because it can’t be created by mixing other paint colors together. Primary yellow paint contains pigments like cadmium yellow or lemon yellow. These bright, warm yellow pigments absorb cooler, blue wavelengths of light and reflect warmer yellow and red wavelengths.
Additive Color Mixing
In additive color mixing, light sources like computer screens combine colors by emitting different wavelengths of light. The primary additive colors are red, green, and blue (RGB). Mixing wavelengths of red and green light stimulates the cones in our eyes to see yellow.
On a computer screen, yellow is made by turning the red and green pixels on at the same brightness level. The red pixel emits around 700nm wavelength light, the green pixel emits around 565nm wavelength light, and the combination is perceived as yellow by the eye.
| Color | Wavelength range |
|---|---|
| Red | ~700nm |
| Green | ~565nm |
So in additive color mixing, yellow is made by combining red and green light. Computer screens, TV screens, and other devices that emit light make yellow this way.
Subtractive Color Mixing
Subtractive color mixing refers to what happens when paints, inks, or dyes absorb some wavelengths of light and reflect others. The primary subtractive colors are cyan, magenta, and yellow. These are the opposite of RGB colors.
When subtractive colors mix, they create new colors by absorbing some wavelengths and reflecting others. For example, yellow ink absorbs blues and violets and reflects reds, oranges, and yellows. Magenta ink absorbs greens and reflects reds and violets. When yellow and magenta mix, they absorb blues and greens but reflect reds – making red.
| Color | Absorbs | Reflects |
|---|---|---|
| Yellow | Blues, violetes | Reds, oranges, yellows |
| Magenta | Greens | Reds, violets |
In subtractive color mixing, no other colors combined make yellow. Yellow ink or paint is a primary color. The bright yellow pigments in paint absorb blue/violet light and reflect yellow and red wavelengths.
Overlapping Color Filters
Overlapping transparent color filters provides another way to visualize subtractive color mixing. For example, overlapping a blue filter and a red filter lets red-orange light through, making the area look yellow.
The blue filter absorbs the orange-red wavelengths while letting blue light through. The red filter does the opposite, absorbing blues and letting red-oranges through. Where they overlap, the only wavelengths left are yellows.
So overlapping blue and red transparent filters results in yellow. This models how subtractive mixing of paints and inks make secondary colors.
Pigment Combinations
While yellow is a primary color in painting, some yellow pigment colors can be created by mixing other pigments.
Mixing pigments relies on subtractive color theory. The combination absorbs some wavelengths and reflects others. Common combinations to make yellow paint or ink are:
- Red + Green
- Magenta + Yellow-green
- Orange + Green
- Red + Blue + White
The red + green combination relies on a warm, orange-ish red and cooler green mixing to a yellow. Magenta pigment reflects reds and absorbs greens, while yellow-green pigment does the opposite. Together they absorb greens and blues to reflect yellow.
Mixing orange (reflecting reds and yellows) and green (absorbing reds and reflecting greens and blues) removes reds and greens, leaving yellow. Finally, combining red, blue, and white absorbs greens and reflects yellow.
These combinations model the principles of subtractive color theory to create yellow pigment without primary yellow paint.
Light Sources
interessantLight sources that emit yellow wavelengths of visible light can also produce yellow as an additive color. Types of light sources that appear distinctly yellow include:
- Candle light: emits warm yellow/orange wavelengths
- Sodium vapor lamps: emit narrow yellow wavelengths
- Fluorescent lights: emit a wide spectrum including yellows
Candle light contains strong output in the red-yellow spectrum, giving it a warm yellow or orange glow. Low pressure sodium vapor lamps emit an intense narrowband double yellow wavelength at 589nm that makes them yellow.
Fluorescent lights have phosphor coatings that emit a broad spectrum of wavelengths. Different phosphor mixtures emit different amounts of yellow wavelengths, contributing to the overall color.
Reflected Light
Objects that selectively reflect yellow wavelengths while absorbing others also appear yellow. Reflectance is determined by the pigments or dyes in the object.
Examples of natural objects that reflect yellow light include:
- Yellow flowers like daffodils
- Yellow autumn leaves
- Yellow fruits like lemons, bananas, pineapple
- Sulfur deposits
These objects contain pigments like carotenoids, flavonoids, and other plant chemicals that absorb violet-blue light and reflect yellow and red wavelengths.
Man-made objects can also be colored with yellow dyes or pigments. Paints, plastics, fabrics, and other materials can appear yellow due to selective reflection of those wavelengths.
Conclusion
Yellow arises in nature from the selective reflection and absorption of different wavelengths of light. It can be produced additively by combining red and green light, or subtractively by absorbing cool blues and reflecting warm yellows and reds. Many combinations of pigments or dyes can create yellow through subtractive color mixing. Pure yellow experiences stimulate the eye’s red and green cones equally to produce the perception of yellow.
