Colors of the Rainbow in Order

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Colors of the Rainbow in Order
The colors of the rainbow in order, from top to bottom, are red, orange, yellow, green, blue, violet. Some lists add indigo between blue and violet.

Listing the colors of the rainbow in order is a common assignment for school children and also fun for adults. However, how many colors you list and which ones they are depends a lot on your age and culture. It turns out there is more than one list!

  • The rainbow actually consists of an infinite number of colors, but most people only perceive around a hundred.
  • For the sake of simplicity, Newton divided the rainbow into 7 colors: red, orange, yellow, green, blue, indigo, and violet.
  • Today, the usual list omits indigo, giving 6 colors of the rainbow. In order from top to bottom, they are red, orange, yellow, green, blue, violet. A modern list of 7 colors is red, orange, yellow, green, cyan, blue, violet.
  • In a double rainbow, the order of colors of the secondary rainbow is reversed: violet, blue, (cyan), green, yellow, orange, red.

The True Number of Colors in the Rainbow

All you need for a rainbow is light and water. The rainbow always appears in the opposite side of the sky from the Sun (or other light source). Since the Sun emits white light, the rainbow consists of the entire visible spectrum. The spectrum is continuous, so there are actually an unlimited number of colors!

However, human beings can’t distinguish all of these colors. Most people can see about one hundred colors in the rainbow. There are other colors possible that result from mixing the colors of the rainbow, giving the average person the ability to see about a million colors. People who have the gene for an additional type of cone in their retina (tetrachromats) see up to a hundred million colors.

Newton’s List of Colors of the Rainbow

Indigo on Color Wheel

Sir Isaac Newton listed 7 colors of the rainbow. In order from top to bottom, they are:

  1. Red
  2. Orange
  3. Yellow
  4. Green
  5. Blue
  6. Indigo
  7. Violet

The acronym Roy G. Biv is a way of remembering the color order. But, there are two problems with Newton’s list. First, the human eye isn’t great at distinguishing indigo from blue or violet. Second, indigo is a tertiary color, so it doesn’t really belong in the list. The primary colors are red, blue, and yellow. Mixing two of the primary colors yields the secondary colors: orange, green, and purple. The tertiary colors, like indigo, require even more color mixing.

7 Colors of the Rainbow in Order

A more modern list of the colors of the rainbow takes its cues from the color wheel:

  1. Red
  2. Orange
  3. Yellow
  4. Green
  5. Cyan
  6. Blue
  7. Violet

If you have a color printer, cyan is a familiar color. Like indigo, it’s a tertiary color, so this list is no better or worse than Newton’s.

6 Colors of the Rainbow

Another popular list uses 6 colors of the rainbow, which are the primary and secondary colors:

  1. Red
  2. Orange
  3. Yellow
  4. Green
  5. Blue
  6. Violet

Which Is Correct?

Unless you are taking a test for a grade, there is no “right” list. The important part is knowing that the top of the rainbow’s arc is red and the bottom color is violet.

Double Rainbow Colors

However, if you see a double rainbow, note that the order of the colors is reversed for the secondary rainbow. The bright, lower rainbow is the primary rainbow and it gets its colors from the reflection, refraction, and dispersion of light by water droplets. Basically, the water droplet acts as a prism. Light gets refracted as it enters the drop, reflected from the back of the droplet, and then refracted again when it exits the water drop.

The secondary rainbow is above the primary rainbow. It has a reversed color order and is fainter in color because it occurs when light gets reflected twice on the interior of the water droplet before leaving it. Secondary rainbows always occur, but they aren’t noticeable unless there is bright sunlight, a lot of water droplets, and a dark background.

So, the order of rainbow colors of a secondary rainbow is:

  1. Violet
  2. Blue
  3. Green
  4. Yellow
  5. Orange
  6. Red

Four Rainbows

It is rare, but if the conditions are right, look for four rainbows in the sky! This happens when there is a calm body of water reflected back enough light that it acts like a second Sun. The first two rainbows are in the opposite side of the sky from the Sun. The second two rainbows are on the opposite side of the sky from the “false” Sun. In both cases, the brighter, lower rainbow has the normal order of colors. The upper, dimmer rainbow has the reversed order of colors.

Not All Rainbows Have All the Colors

If you catch a rainbow when the Sun is low in the sky at sunrise or sunset, you might not see all of the colors. Or, some colors might be thicker and more more prominent than others. At sunrise or sunset, the Sun’s light shifts toward orange and red because it travels through more atmosphere before reaching a viewer’s eyes. A similar effect occurs in rainbows in polluted or smoky skies. Red, orange, and yellow might be the only colors you see or else blue, green, and violet might be thin and faint.

References

  • Allchin, Douglas. “Newton’s Colors“. SHiPS Resource Center.
  • Gage, John (1994). Color and Meaning. University of California Press. ISBN 978-0-520-22611-1.
  • Jordan, G.; Deeb, S.S.; Bosten, J.M.; Mollon, J.D. (20 July 2010). “The dimensionality of color vision in carriers of anomalous trichromacy”. Journal of Vision. 10 (8): 12. doi:10.1167/10.8.12
  • Kershner, Kate (July 26, 2016). “Lucky Tetrachromats See World With Up to 100 Million Colors“. HowStuffWorks.
  • Waldman, Gary (1983). Introduction to Light: The Physics of Light, Vision, and Color (2002 revised ed.). Mineola, New York: Dover Publications. ISBN 978-0486421186.