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Northern Lights, Color Perception, and Accessibility

Pink hues on the night sky with clouds above trees and a house.

Last Friday, May 10, the skies over New York State put on an unexpected show: the Northern Lights, or Aurora Borealis. This phenomenon is typically reserved for more northern latitudes but, due to heightened solar activity, was visible as far south as Italy and Florida.

Despite the cloudy weather earlier in the evening, the skies cleared close to midnight, giving those who stayed up a chance to witness this rare event.

While the human eye can see the aurora, capturing its full range of colors often requires a camera. On this particular night, I experienced this firsthand. As I looked up, I did not see the aurora, but my phone’s camera revealed pink hues that my eyes could not detect.

This discrepancy led me to explore why cameras often see colors in the aurora that our eyes miss, and how this relates to broader issues of color perception, color blindness, and accessibility.

The Science Behind the Northern Lights

The Northern Lights are created when charged particles from the sun interact with the Earth’s magnetic field and atmosphere. These particles collide with gases like oxygen and nitrogen, producing light.

The color of the aurora depends on the type of gas and the altitude at which the collisions occur:

  • Green: Oxygen at lower altitudes (up to 150 miles)
  • Red/Pink: Oxygen at higher altitudes (above 150 miles)
  • Blue/Purple: Nitrogen at lower altitudes (up to 60 miles)
  • Crimson: Nitrogen at higher altitudes (above 60 miles)

Human vision is more sensitive to green light, which is why green auroras are more commonly seen. Red and pink auroras, while still visible to the human eye, are less easily perceived due to the lower sensitivity of our eyes to these colors, particularly in low-light conditions. Similarly, the blue and purple hues produced by nitrogen are often faint and more challenging to see with the naked eye.

Color Perception and Cameras

Cameras have sensors that can capture a wider range of light wavelengths than the human eye, making them more effective at detecting the full spectrum of auroral colors.

I remember seeing the aurora for the first time in Finland a few years ago. I noticed green colors and took a picture of the aurora. To my surprise, my camera also captured the pink hues of the aurora, while I could only see the green with my own eyes. This phenomenon highlights an essential aspect of color perception: what we see is not always the complete picture.

The photo at the top of this article is the one I took on Friday night, showing pink hues in the skies. I didn’t see them, but my iPhone camera did.

Color Blindness and Accessibility

Color blindness affects approximately 1 in 12 men and 1 in 200 women worldwide. The most common form is red-green color blindness, where individuals have difficulty distinguishing between these colors. This variation in color perception means that people experience the world differently, and what might be clear and vibrant to one person could be dull or indistinguishable to another.

This has significant implications for accessibility, especially in design. Here are some key considerations for ensuring accessibility in color design:

  • Contrast: Ensure sufficient contrast between foreground and background elements. High contrast improves readability for everyone, including those with color blindness.
  • Color Combinations: Avoid relying solely on color to convey information. Use patterns, shapes, or text labels as additional indicators.
  • Testing: Use tools to test your designs for color blindness. Simulators and color contrast checkers can help you see how your work appears to individuals with different types of color blindness.

Practical Examples

Consider these practical tips to improve accessibility in design:

  • Text and Background: Always ensure a strong contrast between text and its background. Dark text on a light background or vice versa is usually the best practice. For instance, black text on a white background offers excellent contrast.
  • Visual Indicators: Use more than color to distinguish elements. For example, in charts, combine colors with different shapes or patterns. This way, even if someone cannot differentiate the colors, they can still understand the information through the shapes or patterns.
  • Accessibility Tools: Utilize web tools and browser extensions that simulate color blindness. This can help designers understand how their work appears to users with different color perceptions.

Conclusion

The experience of seeing the Northern Lights, and realizing the limitations of human color perception, underscores the importance of considering color blindness and accessibility in design. While our eyes might not always capture the full spectrum of colors in phenomena like the aurora, technology can bridge this gap. Similarly, thoughtful design can ensure that everyone, regardless of their color perception abilities, can access and enjoy visual information.

The Northern Lights serve as a beautiful reminder of the wonders of our natural world and the importance of inclusivity in our designed environments. By embracing accessible design principles, we can create a world where visual experiences are shared and appreciated by all.

Does your business need more accessibility awareness and training? Contact me for consulting services.

Published in Accessibility

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