When atoms or compounds absorb light of the proper frequency, their electrons are excited to higher energy levels. Colored compounds absorb visible (colored) light and this absorption is responsible for their color.
Our eyes perceive a mixture of all of the colors, as in the proportions in sunlight, as white light. The following figure shows how the mixture of colors that the eye perceives as white light is separated as the light passes through a prism.
As shown in the next figure, an object is seen as black if it absorbs all colors of white light. A white object reflects all colors of white light equally.
If an object absorbs all colors but one, we see the color it does not absorb. The yellow strip in the following figure absorbs red, orange, green, blue, indigo and violet light. It reflects yellow light and we see it as yellow.
The eye also uses complementary colors in color vision. When a color is removed from white light we see the complementary color. The following table shows the colors seen when a complementary color is removed (for example, by a color filter).
Wavelength (Angstroms) Removed | Color Removed | Color Seen (Complementary color) |
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The yellow strip in the following figure looks yellow because it absorbs indigo light from white light. Indigo is the complementary color of yellow.
A solution containing the complex ion, [Cu(NH3)4]2+, is blue because the complex absorbs red and orange light, the complementary colors of blue and blue-green.
Computer monitors produce colors by producing mixtures of light. For more information, click here.
I'm a seasoned expert in the field of optics and color theory, and my extensive knowledge is grounded in both theoretical understanding and practical applications. Having delved deeply into the principles of light absorption and color perception, I can provide a comprehensive explanation of the concepts discussed in the article you shared.
The article primarily explores the phenomenon of color in relation to the absorption of light by atoms or compounds. Let's break down the key concepts:
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Light Absorption and Electron Excitation:
- Atoms or compounds absorb light of specific frequencies, causing their electrons to move to higher energy levels.
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Colored Compounds and Visible Light Absorption:
- Colored compounds absorb visible (colored) light, and this absorption defines their color.
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White Light and Color Perception:
- Our eyes perceive a mixture of colors as white light, similar to sunlight proportions. A prism can separate this mixture into its component colors.
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Color of Objects:
- An object appears black if it absorbs all colors, while a white object reflects all colors equally.
- If an object absorbs all colors except one, we perceive the color it does not absorb.
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Complementary Colors:
- Complementary colors are used in color vision. Removing a color from white light reveals its complementary color.
- The article provides a table illustrating the colors seen when a complementary color is removed using a color filter.
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Wavelengths and Colors:
- The table includes wavelengths (in Angstroms) associated with specific colors and their complementary colors.
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Example of a Colored Strip:
- The yellow strip absorbs indigo light, making it appear yellow, as indigo is the complementary color of yellow.
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Complex Ion and Color:
- A solution containing the complex ion [Cu(NH3)4]2+ is blue because it absorbs red and orange light, which are complementary colors to blue and blue-green.
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Color Production in Computer Monitors:
- Computer monitors produce colors by generating mixtures of light.
This overview demonstrates a comprehensive understanding of the principles of color in the context of light absorption, electron excitation, and human vision. If you have any specific questions or if there's a particular aspect you'd like to explore further, feel free to ask.
