Orange is a color that is often associated with warmth, enthusiasm, and creativity. But where does this vibrant hue come from? In physics and optics, orange is a result of how our eyes perceive different wavelengths of light.
The Visible Spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. The wavelengths of light in the visible spectrum range from about 380 to 740 nanometers (nm). The longest wavelengths we can see are perceived as red, while the shortest are seen as violet.
In between these extremes, the wavelengths corresponding to orange light are around 590-620 nm. Sunlight contains light of all visible wavelengths. When an object absorbs all wavelengths except those in the orange range, our eyes see it as orange.
How Our Eyes Detect Color
The human eye has specialized cells called cone cells that allow us to see color. There are three types of cone cells, each of which is sensitive to a broad range of wavelengths:
- S-cones: sensitive to short wavelengths (violet to green)
- M-cones: sensitive to medium wavelengths (green to orange)
- L-cones: sensitive to long wavelengths (orange to red)
When light hits the eye, the cone cells are stimulated to different degrees depending on the wavelengths present. The combination of stimulations creates an electrical signal that is sent to the brain. The brain interprets these signals as color.
For us to see orange, the M-cones need to be stimulated more than the S-cones and L-cones. This occurs when orange wavelengths around 590-620nm reach the eye.
Mixing Colors of Light
Orange can also be created by mixing wavelengths of light. Red light and yellow light can be combined to make orange. This is known as an additive mix, because the light waves are being added together.
The primary colors of light are red, green, and blue (RGB). Mixing wavelengths of red and green light stimulates our M-cones and L-cones to make yellow light appear orange. The table below shows some examples of mixtures that produce orange:
| Color 1 | Color 2 | Result |
|---|---|---|
| Red | Yellow | Orange |
| Red | Green | Orange |
Pigments and Dyes
Unlike light, pigments and dyes create color through subtraction. They absorb some wavelengths and reflect others. The subtracted or absorbed colors are what we see as the pigment or dye’s color.
The primary colors for pigments are magenta, yellow, and cyan (MYC). When two of these are combined, they produce secondary colors by absorbing more wavelengths. Mixing magenta and yellow pigments creates an orange color by absorbing blues and greens:
| Pigment 1 | Pigment 2 | Absorbs | Reflects | Appears |
|---|---|---|---|---|
| Magenta | Yellow | Blues, Greens | Reds, Oranges | Orange |
This is why paints, dyes, and other pigments rely on different primary colors than light. They create color in a subtractive way, while light adds wavelengths together.
Natural Sources of Orange
In nature, there are a few common sources that produce orange colors:
- Plants – Carotenoids like lutein reflect orange/yellow light. Many flowers, fruits, and autumn leaves contain these pigments.
- Minerals – Iron oxides create orange/red hues in minerals like clay, rust, and sandstone.
- Animals – Some birds, insects, fish obtain orange colors from diet-derived pigments.
- Sunrise/Sunset – When sunlight passes through more atmosphere, shorter blue wavelengths scatter leaving longer orange/red waves.
These natural sources all utilize the physics of light absorption, reflection, and scattering to produce orange tones. The specific mechanisms vary, but they all remove some visible wavelengths while reflecting or transmitting those in the orange region.
Why Orange Appears Warm
Colors can seem to have different psychological associations or symbolism. Orange is commonly associated with warmth, heat, enthusiasm, and energy.
This may be partly explained by the correlation between orange/red hues and heat in physical objects. As an object heats up, it begins glowing, moving from red to orange to yellow to white as temperature increases. Heat, fire, and molten metal give off orange/red light.
Longer orange/red wavelengths also have lower frequencies, so they carry less energy. Our brains may associate this with the warmth of places that store and radiate heat slowly. Shorter blue wavelengths have higher frequencies and energy, evoking coolness.
Through these natural associations between color and temperature, orange and red hues came to symbolize concepts like warmth, passion, and energy in human culture.
Using Orange in Design
Orange is a bold, energetic color that stands out in design. It can convey excitement, youthful enthusiasm, and creativity. Orange helps grab attention, but can risk seeming loud or abrasive if overused.
Here are some tips for working with the color orange:
- Use sparingly as an accent color against neutrals like white, black, or gray
- Pair with blue, brown, or green as complementary colors
- Lighten tones for a cheerful, non-aggressive look
- Use for highlighting important elements you want viewers to notice
- Avoid large blocks of bright orange, which will dominate a design
Fields like marketing, healthcare, toys/games, and food often utilize orange to stand out, highlight a brand/theme, and evoke energy or fun. Just keep orange as an accent, rather than the main color for a balanced, inviting design.
Orange in Nature and Culture
Orange holds symbolism related to warmth, enthusiasm, whimsy, and vibrance across cultures. Here are some examples of orange themes:
- Sunrises, sunsets, autumn leaves
- Citrus fruits, carrots, pumpkins
- Monarch butterflies, goldfish, orange cats
- The Color of Buddhism and Hinduism
- Netherlands national color, representing William of Orange
- Prison uniforms, safety vest, traffic cones
- Warning signs, alerts, calls to action
Orange draws attention wherever it occurs in nature. It signals danger, ripe fruit, falling leaves, and more. Humans have adapted it for similarly eye-catching purposes across many cultural realms.
Conclusion
Orange is a vibrant result of specific wavelengths of light. It lies between red and yellow in the visible spectrum. Specialized cells in our eyes detect these mediump wavelengths, signaling orange to our brains. Mixing light or pigments can also produce orange by combining reds, greens, and yellows. Orange has come to symbolize energy, warmth, enthusiasm, and bold highlighting. Knowledge of its optical and psychological properties helps designers use orange effectively.
