Filters work by selectively absorbing or transmitting certain wavelengths (colors) of light while blocking others. When white light (which contains all colors) passes through a filter, the filter absorbs some colors and allows others to pass through, resulting in the light appearing colored.
Here's a breakdown of how this process works:
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White Light: White light is composed of all the colors of the visible spectrum (red, orange, yellow, green, blue, indigo, and violet).
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Filter Material: Filters are made of materials that have specific absorption properties. This means that certain molecules within the filter material are able to absorb light of particular wavelengths.
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Absorption: When white light strikes the filter, the molecules within the filter absorb specific wavelengths of light. The colors that are absorbed are effectively removed from the light.
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Transmission: The wavelengths of light that are not absorbed by the filter material are transmitted through it. These transmitted wavelengths are the colors that we see.
Example:
Imagine a red filter.
- White light enters: White light, containing all colors, shines onto the red filter.
- Absorption occurs: The filter material absorbs most of the colors (e.g., blue, green, yellow).
- Red light passes through: Only the red wavelengths of light are allowed to pass through the filter.
- Observed color: When we look through the filter, we see only red light.
Types of Filters:
Filters can be designed to selectively transmit:
- Specific colors: Like the red filter example, filters can transmit specific colors of light.
- Wavelength ranges: Some filters allow a broader range of wavelengths to pass through, creating broader color effects.
- Specific polarizations: Polarizing filters block light waves that are oscillating in certain directions.
- Ultraviolet (UV) or Infrared (IR) light: These filters block visible light and only allow UV or IR light to pass through.
In summary, filters selectively absorb certain colors of light, allowing the remaining colors to pass through, thus altering the color composition of the light.
