Introduction
Yes, pink is considered part of the visible light spectrum. The visible light spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. It ranges in wavelength from approximately 380 nanometers to 750 nanometers. Pink is a mix of red and violet light waves and resides between red and violet on the visible spectrum.
The Visible Light Spectrum
The visible light spectrum is the section of the full electromagnetic spectrum that the human eye can detect. The electromagnetic spectrum encompasses all types of electromagnetic radiation, from radio waves to gamma rays. The visible spectrum makes up just a small sliver of the full electromagnetic spectrum, between infrared light and ultraviolet light.
The visible spectrum runs from violet light with short wavelengths of around 380 nanometers to red light with longer wavelengths of around 750 nanometers. In between lie the other colors of the rainbow in order of decreasing wavelength: blue, green, yellow, and orange. White light contains a mixture of all the colors of the visible spectrum. When white light passes through a prism, the colors separate based on their wavelengths, creating the familiar rainbow spectrum.
| Color | Wavelength (nm) |
|---|---|
| Violet | 380-450 |
| Blue | 450-495 |
| Green | 495-570 |
| Yellow | 570-590 |
| Orange | 590-620 |
| Red | 620-750 |
Where Does Pink Fit In?
Pink is a mix of red and violet light. It sits between the two colors on the visible spectrum, in the area that overlaps between red’s longer wavelengths and violet’s shorter wavelengths. Pink isn’t associated with a single wavelength or narrow band of wavelengths like the other colors. Rather, it arises when red and violet combine to make an intermediary hue. Different shades of pink correspond to different ratios of red to violet light.
Pink is considered a tertiary color, meaning it is created by combining two primary colors – in this case, red and violet. The primary colors are red, blue, and green because they can’t be created by mixing other colors but combine to produce all other colors. Violet may substitute for blue as a primary in some color models.
While pink does not occupy its own discrete section of the visible spectrum, its presence as a mix of red and violet wavelengths firmly places it within the spectrum of visible light. When white light, containing the full rainbow of colors, shines on an object that absorbs all but the red and violet wavelengths, the light reflected back appears pink to our eyes.
Properties of Pink Light
What are some key properties of pink light and how do they compare to the properties of red and violet light? Here is an overview:
Wavelength: Pink light has an intermediary wavelength between red and violet. Exact values depend on the specific shade of pink. A deep pink closer to red will have a longer wavelength around 700 nm while a light pink nearer violet will be around 400 nm.
Frequency: Frequency is inversely related to wavelength, so pink light also has an intermediate frequency between red and violet. Pink frequencies range from about 400 THz on the violet side to 770 THz for deep pink hues.
Energy: Shorter wavelengths and higher frequencies correspond to higher energies. Since pink is intermediate between red and violet, so is its light energy. Violet light carries the most energy within the visible spectrum.
Speed: All visible light travels at the same speed in a vacuum – approximately 300,000 km/s. The speed is related to the medium rather than the wavelength or frequency.
So in summary, pink light has spectral properties sitting between the extremes of the red and violet portions of the visible spectrum. Mixing these two primary colors produces pink’s signature intermediate characteristics.
Seeing Pink Light
The human eye has specialized cells called cone cells that allow us to see color. There are three types of cones tuned to different wavelengths of light. Signals from the cone cells are processed by the brain to let us perceive color.
The visible spectrum from violet to red corresponds roughly to the peaks in sensitivity of the three cone types. However, there is considerable overlap between the cone sensitivity curves. This allows the cones to work together to detect colors like pink that don’t have a single associated wavelength.
Here is how we perceive pink light:
– Long wavelength red light strongly stimulates the L cones.
– Shorter wavelength violet light stimulates the S cones.
– Pink light, with its blend of wavelengths, activates both the L and S cones to varying degrees.
– The brain combines and interprets the signals from the two cone types as the color pink.
– The different ratios of L to S cone stimulation elicit perceptions of different pink shades and saturations.
So while pink does not correlate with a single cone type, its mix of red and violet wavelengths activates two cone types in a unique pattern that the brain recognizes as pink. This places pink squarely within our visible color experience.
Applications of Pink Light
Pink light and pink lasers have a variety of interesting uses and applications:
– Pink laser light can be produced from a neodymium or titanium-sapphire laser using an organic dye like rhodamine 6G to generate the pink wavelength.
– Pink laser levels use a pink beam for enhanced visibility compared to traditional red levels. This can improve leveling accuracy.
– Pink light is used in horticulture to influence plant growth and flowering, including inhibiting excessive stem elongation.
– Pink LED light has been studied for its potential to increase milk production in dairy cows.
– Pink light red therapy is a cosmetic skin treatment said to have anti-aging and anti-acne benefits.
– Pink soft laser light is used therapeutically to promote wound healing.
– Pink fluorescent light has been reported to have a calming effect compared to more stimulating blue light.
So pink light, while not distinct spectrally, has many intriguing applications across lasers, agriculture, animal husbandry, dermatology, and mental health. Its mix of wavelengths offers unique properties compared to other colors of light.
Conclusion
In summary, while pink does not occupy its own narrow band on the electromagnetic spectrum, its existence as a mixture of red and violet wavelengths places it firmly within the visible color spectrum. Pink arises when red and violet light combine to stimulate both the L and S cone cells in our eyes, creating the characteristic hue. So whether produced by lasers, LEDs, or pigments, pink and its many shades have a clear place among the rainbow of spectral colors.
