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Is it violet first or indigo?

This is an important question for artists, scientists, and anyone interested in the order of colors in the visible spectrum. The visible spectrum is the range of electromagnetic radiation that can be seen by the human eye. It consists of 7 colors: red, orange, yellow, green, blue, indigo, and violet. But there has been some debate over the years about whether indigo or violet comes first when listing the colors in order.

Quick Answers

Traditionally, indigo comes before violet when listing the colors of the rainbow in order. This is the order originally proposed by Isaac Newton in the 17th century. However, some argue that violet should come before indigo, as violet has a shorter wavelength and higher frequency than indigo. So there is still some disagreement among experts on the proper order.

The Visible Spectrum

The visible spectrum is the part of the electromagnetic spectrum that can be seen by the human eye. Electromagnetic radiation in this range of wavelengths is called visible light. The visible spectrum ranges from wavelengths of about 380 nanometers (violet) to about 740 nm (red).

Within this spectrum of visible light, there are 7 colors that have roughly corresponding wavelengths:

Color Wavelength range (nm)
Red ~700–635
Orange ~635–590
Yellow ~590–565
Green ~565–495
Blue ~495–450
Indigo ~450–420
Violet ~420–380

These 7 color bands make up the rainbow and the order is commonly memorized using the acronym ROY G. BIV. But the question remains – should indigo or violet come first in this order?

History of ROYGBIV Order

The traditional order of RED, ORANGE, YELLOW, GREEN, BLUE, INDIGO, VIOLET originated with Isaac Newton in the late 17th century. Newton was the first to demonstrate that white light could be split into a spectrum of different colors using a prism. He identified 7 main color bands, which matched the 7 notes of the musical scale, and ordered them with indigo before violet.

This order was popularized in 1814 through a poem by Newtonian scientist William Whewell, which helped memorize the colors as ROY G. BIV. This indigo-first order stuck and became the convention for listing the colors of the rainbow throughout the 18th-20th centuries.

Arguments for Violet First

In recent years, some scientists have argued that violet should come before indigo in the ROYGBIV order. The main reasons are:

  • Violet has a shorter wavelength (higher frequency) than indigo – The wavelength of violet light is about 380-450 nm, while indigo is 450-420 nm. Higher frequency colors are often listed first.
  • The human eye detects violet light better than indigo – The eye’s luminosity function peaks closer to violet wavelengths than indigo.
  • There is not a clear distinction between violet and indigo – The transition between these color bands is quite smooth, so separating them is somewhat arbitrary.

For these reasons, some representations of the visible spectrum now order the colors with violet first as: RED, ORANGE, YELLOW, GREEN, BLUE, VIOLET, INDIGO. In this ordering, violet more logically comes before indigo based on physical properties of light.

Arguments for Keeping Indigo First

However, there are also reasons to keep the original ROYGBIV ordering with indigo first:

  • Traditionally indigo comes first – This ordering has been used for centuries, originally proposed by Newton.
  • It maintains consistency with the musical scale analogy – Newton chose 7 colors to match the 7 notes of the diatonic scale.
  • There is still debate on violet vs. indigo distinction – Not all scientists agree that violet has a clear priority over indigo.
  • ROYGBIV is memorized by generations – The acronym ROY G. BIV is a familiar mnemonic, so people expect indigo to precede violet.

So keeping the original sequence may avoid confusion, preserve tradition, and recognize that the violet/indigo debate is still not fully settled scientifically.

How Color Ordering Is Used

The main contexts where the order of violet and indigo comes into play include:

  • Listings of visible spectrum color order
  • Charts/diagrams labeling rainbow colors
  • ROYGBIV memorization mnemonics
  • Ordering color mixing guides (for paint, light, etc.)
  • Ranking frequencies/wavelengths from high to low

But in many practical applications, the specific sequence doesn’t matter too much. For example, when making a rainbow art project, using colors in ROYGBIV or ROYGBVI order will look essentially the same. And digital color models like RGB don’t distinguish indigo and violet at all.


In summary, while there are good arguments on both sides, traditionally indigo comes first before violet in the commonly accepted order of colors in the visible spectrum. But the debate continues among scientists, artists, and others about whether violet should logically precede indigo given its shorter wavelength. Ultimately, context and convention may dictate which order is preferred in a given situation.

The traditional ROYGBIV sequence is deeply ingrained through mnemonics and historical precedent. But Violet-first ordering does have scientific rationale and is gaining advocates. In either case, recognizing that indigo and violet are the two colors in closest contention can lead to interesting discussions about the very nature of color itself.