Colors

Street Light

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All the while, I’ve been wondering why orange or amber color is always the choice for street lamps. Is it because of human like orange or amber more?

Actually, the choice of using orange or amber light for street lamps is based on several factors, including visibility, energy efficiency, and minimizing light pollution. Here’s why orange or amber light is often preferred over red light for street lighting:

1. Visibility and Contrast: Orange/amber light provides good visibility and contrast for drivers and pedestrians, especially in various weather conditions such as fog, rain, or snow. Red light, on the other hand, may not offer the same level of contrast and visibility, making it less suitable for illuminating streets.

2. Human Perception: Human eyes are more sensitive to orange and amber wavelengths, allowing better perception of details and objects under this lighting compared to red light. Red light is less effective in providing sufficient illumination for activities that require good visibility.

3. Light Penetration and Distance: Both red and orange light can travel relatively far, but their ability to penetrate through obstacles, like fog or rain, may differ. The choice of color for street lighting is based on various factors, including how the light interacts with the environment, rather than simply how far it can travel.

4. Light Pollution: Reducing light pollution is an important consideration in outdoor lighting. Using a specific color of light, such as orange or amber, helps minimize light pollution by reducing the amount of light that scatters into the sky and nearby areas.

The orange or amber color of street lamps is typically due to the type of light bulb used, particularly high-pressure sodium (HPS) or low-pressure sodium (LPS) lamps. These lamps emit light in the yellow-orange part of the spectrum.

In summary, while red light can travel a certain distance, it may not provide optimal visibility, contrast, and efficiency for street lighting purposes. Orange or amber light strikes a balance between visibility, efficiency, human perception, and minimizing light pollution, making it a preferred choice for street lighting.

Light Penetration & Night Vision

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In terms of light penetration through various substances, blue and violet light have shorter wavelengths and higher energy, allowing them to penetrate through certain materials more effectively compared to longer-wavelength colors like red or orange.

Here’s a general overview of light penetration for different colors:

• Blue and Violet Light: Blue and violet light have shorter wavelengths and higher energy, enabling them to penetrate through substances like water and some other materials more effectively. This is why underwater environments often appear blue or greenish-blue due to the scattering and absorption of longer-wavelength light.

• Green Light: Green light has a moderate wavelength and can penetrate water to some extent, but not as effectively as blue and violet light.

• Yellow and Orange Light: Yellow and orange light have longer wavelengths compared to blue and green light. They penetrate substances like water less effectively and are often absorbed or scattered more readily, reducing their ability to travel through materials.

• Red Light: Red light has the longest wavelength among visible colors. It is absorbed and scattered more easily in water and other substances, resulting in less penetration compared to shorter-wavelength colors like blue and violet.

It’s important to note that the ability of light to penetrate substances also depends on factors such as the specific material, its density, purity, and any impurities present. Additionally, the scattering and absorption properties of different materials play a significant role in determining how light penetrates and interacts with them.

For medical imaging or other applications requiring deeper tissue penetration, specific wavelengths of light, often in the near-infrared range, are used because they can penetrate skin and other biological tissues more effectively.

Usage of Red Light

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Red light is often used to signal alerts or indicate warnings to humans for several reasons, despite its relatively lower penetration compared to shorter-wavelength lights:

• Attention and Visibility: Red light is easily perceived by the human eye and stands out well against many backgrounds. It is a color that naturally draws attention, making it effective for alerting and signaling.

• Cultural Associations: Red has cultural associations with warning, caution, and danger. Over time, societies have adopted red as a color for signaling alarms, stop signs, traffic lights, and other warning indicators.

• Night Vision Preservation: Red light is less likely to disturb night vision compared to brighter, higher-energy colors. When used in low-light or dark environments, like in the cockpit of an aircraft or on a ship, red light allows individuals to maintain better night vision while still providing enough illumination for reading or navigating.

• Reduced Disruption to Sleep: Exposure to blue or white light can interfere with circadian rhythms and disrupt sleep patterns. Red light, being at the longer-wavelength end of the visible spectrum, has less impact on melatonin production and is often used in low-light settings to minimize disturbances to sleep.

• Safety in Certain Environments: In environments where the use of white or bright lights might be dangerous (e.g., astronomy observatories, submarines, military operations), red light is employed to maintain low light levels for safety without compromising visual awareness.

In summary, while red light may not penetrate as deeply into materials as shorter-wavelength light, its visibility, attention-grabbing nature, cultural associations, and suitability for low-light environments make it a practical choice for signaling alerts and warnings to humans.

Penetration Rate vs Visibility Rate

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Penetration rate and visibility rate are related but not the same thing. Let’s clarify the difference:

Penetration Rate: Penetration rate refers to how deeply a light wave can travel through a material before being absorbed, scattered, or attenuated. Shorter-wavelength light, like blue and violet light, typically penetrates materials more effectively than longer-wavelength light, like red light.

Visibility Rate: Visibility rate refers to how easily a light can be seen and distinguished by the human eye. It’s about how well a light is perceived in terms of brightness and contrast against its background, regardless of its ability to penetrate through materials.

In general, shorter-wavelength light penetrates better through materials, but this doesn’t necessarily mean it’s more visible to the human eye. Visibility is influenced by factors like the sensitivity of human vision to different wavelengths (spectral sensitivity), the contrast against the background, and other optical properties of the environment.

For example, red light may not penetrate as far through fog or water compared to blue light, but it can still be more visible to the human eye in those conditions due to its higher contrast and better perception by our eyes.

In applications like signaling and lighting, both penetration and visibility are important considerations. The choice of light color is often a balance between these factors, depending on the specific use case and the desired outcome.

Light of Choices

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During the day with heavy rain or fog, and at night, the choice of lighting for a car is crucial to ensure visibility and safety. Here are recommendations for both scenarios:

1. Daytime with Heavy Rain or Fog:

   1. Recommended: White or Amber Light
   2. Reasoning:
      1. White light provides good visibility and contrast during the day, making it easier for other drivers to see your vehicle through heavy rain or fog.
      2. Amber light (yellow-orange) is also effective as it cuts through fog and rain better than other colors and helps in improving visibility.

2. Nighttime:

   1. Recommended: White and Red Light
   2. Reasoning:
      1. White light, including headlights and front-facing lights, is essential for illuminating the road ahead and providing adequate visibility during the night.
      2. Red light is used for rear-facing lights, like tail lights and brake lights. It’s easily distinguishable and indicates the position and actions of the vehicle to other drivers.

Light Groups Comparison

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Below is a comparison of different color groups, including invisible color groups, based on energy, visibility, penetration rate, and wavelength.

Please note that the provided information is a general comparison and may vary slightly based on specific circumstances and contexts.

Notes:

• Energy: Indicates the energy level associated with each color, with blue/violet having the highest energy and red having the lowest.
• Visibility: Refers to how easily the color is perceived by the human eye, with all colors being generally good for visibility.
• Penetration Rate: Describes the ability of the color to penetrate through substances, with shorter-wavelength colors (blue/violet) penetrating more effectively than longer-wavelength colors (red).
• Wavelength (nm): Represents the approximate range of wavelengths for each color group.

Black and White Lights

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Black is not considered a color in the traditional sense when it comes to light. Instead, black is the absence or complete absorption of visible light. When you perceive an object as black, it means that the surface of the object absorbs most of the visible light that falls on it, rather than reflecting or transmitting it.

Therefore, black doesn’t have a specific wavelength associated with it because it’s defined by the absence of light.

White light is not associated with a specific wavelength; instead, it is a combination of all visible wavelengths of light. When you see white light, you’re perceiving a mix of various colors across the visible spectrum. The exact composition and proportion of these colors determine the quality and appearance of the white light.

In physics, white light is often described as a combination of all colors in the visible spectrum. When white light is passed through a prism, it is dispersed into its constituent colors, resulting in a rainbow-like spectrum known as a continuous spectrum. This dispersion of colors is due to the differing wavelengths of each color in the white light.

In summary, white light is not associated with a single wavelength; rather, it encompasses all visible wavelengths, blending them together to create what we perceive as white.

Easter Eggs: Theme Color Used

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{{< swatches "#303030" "#BDBDBD" "#808080" >}}