Electromagnetism And Radiation Codexery

Visible spectrum

The range of electromagnetic radiation visible to the human eye.

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The visible spectrum is the band of the electromagnetic spectrum that is visible to the human eye.[1] The wavelengths that a typical human eye can detect fall within a range of roughly 380 to 750 nanometers.[2] The exact limits of this range are not fixed and can differ from one person to another.[3]

Quick Facts

Wavelength range
380–750 nm (typical)
Extended limits
310 nm (UV) to 1100 nm (NIR) under optimal conditions
Named colors by newton
  • red
  • orange
  • yellow
  • green
  • blue
  • indigo
  • violet
Key historical figures
  • Roger Bacon
  • Isaac Newton
  • Johann Wolfgang von Goethe
  • Thomas Young
  • Hermann von Helmholtz

Facts from the source article.

Key facts and history

Newton originally divided the spectrum into six named colors: red, orange, yellow, green, blue, and violet.[4] He later added indigo as the seventh color since he believed that seven was a perfect number.[4] According to available evidence, the colors Newton labeled "indigo" and "blue" do not match what those terms signify today.[5] When Newton's description of the colors from a prism is compared to a modern color image of the visible spectrum, his "indigo" aligns with what is now called blue, and his "blue" aligns with what is now called cyan.[5]

During the early 1800s, William Herschel (infrared) and Johann Wilhelm Ritter (ultraviolet) were among those who identified and described light existing beyond the visible range.[6] Not every color that humans can perceive is present within the spectrum.[7] Colors like pink and magenta, which are not saturated, are missing from the spectrum because they require a combination of multiple wavelengths to be produced.[7]

What the research sources say

The Hyperphysics resource states that the visible spectrum is roughly from 700 nm (red end) to 400 nm (violet end).[8] It notes that monochromatic light like the helium-neon laser is red (632 nm) because it falls in the appropriate wavelength range.[8] The Hyperphysics resource defines pure colors in terms of the wavelengths of light.[8]

References

  1. Wikipedia, "Visible spectrum" (CC BY-SA 4.0), which cites: Pedrotti, "Introduction to Optics", Cambridge University Press, December 21, 2017, p. 7–8; "What Is the Visible Light Spectrum?", ThoughtCo (we also read that source) en.wikipedia.org
  2. Wikipedia, "Visible spectrum" (CC BY-SA 4.0), which cites: Starr, Cecie, "Biology: Concepts and Applications", Thomson Brooks/Cole, 2005, p. 94 (original not read by us) en.wikipedia.org
  3. Wikipedia, "Visible spectrum" (CC BY-SA 4.0), which cites: "The visible spectrum", Britannica, 27 May 2024; D. H. Sliney, "What is light? The visible spectrum and beyond", Eye, February 2016, p. 222–229; W. C. Livingston, "Color and light in nature", Cambridge University Press, 2001; Grazyna Palczewska, "Human infrared vision is triggered by two-photon chromophore isomerization", Proceedings of the National Academy of Sciences, December 2014, p. E5445–E5454 (original not read by us) en.wikipedia.org
  4. Wikipedia, "Visible spectrum" (CC BY-SA 4.0), which cites: Isacoff, "Temperament: How Music Became a Battleground for the Great Minds of Western Civilization", Knopf Doubleday Publishing Group, 16 January 2009, p. 12–13 (original not read by us) en.wikipedia.org
  5. Wikipedia, "Visible spectrum" (CC BY-SA 4.0), which cites: Evans, "The perception of color", Wiley-Interscience, 1974; McLaren, "Newton's indigo", Color Research & Application, March 2007, p. 225–229; Waldman, "Introduction to light: the physics of light, vision, and color", Dover Publications, 2002, p. 193 (we also read that source) en.wikipedia.org
  6. Wikipedia, "Visible spectrum" (CC BY-SA 4.0), which cites: "The Cambridge History of Science: The Modern Physical and Mathematical Sciences", Cambridge University Press, 2003, p. 278; John C. D. Brand, "Lines of light: the sources of dispersive spectroscopy, 1800–1930", CRC Press, 1995, p. 30–32 (original not read by us) en.wikipedia.org
  7. Wikipedia, "Visible spectrum" (CC BY-SA 4.0), which cites: Nave, "Spectral Colors", Hyperphysics; "Colour - Visible Spectrum, Wavelengths, Hues Britannica", www.britannica.com, 2024-09-10 (we also read that source) en.wikipedia.org
  8. Nave, "Spectral Colors", Hyperphysics. facts only, no text reused. hyperphysics.phy-astr.gsu.edu

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Visible spectrum (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

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Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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