Roy G. Biv is a
mnemonicA mnemonic device is a mind memory and/or learning aid. Commonly, mnemonics are verbal—such as a very short poem or a special word used to help a person remember something—but may be visual, kinesthetic or auditory. Mnemonics rely on associations between easy-to-remember constructs which can be...
for the sequence of hues in the
visible spectrumThe visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nm...
, in
rainbowA rainbow is an optical and meteorological phenomenon that causes a spectrum of light to appear in the sky when the Sun shines onto droplets of moisture in the Earth's atmosphere...
s, and in order from longest to shortest wavelength:
- Red
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked human eye...
- Orange
- Yellow
Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–580 nm is yellow, as is light with a suitable mixture of somewhat longer and shorter wavelengths...
- Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
- Blue
Blue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
- Indigo
- Violet
As the name of a color, violet is used in two senses: first, referring to the color of light at the short-wavelength end of the visible spectrum, approximately 380–420 nm when indigo is recognized as a distinct color, or more commonly 380–450 nm...
Another way to remember it is:
Richard
Of
York
Gave
Battle
In
Vain.
The colors are arranged in the order of decreasing
wavelengthIn physics, the wavelength of a sinusoidal wave is the spatial period of the wave – the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s, with red being 650 nm and violet being about 400 nm.
Although the spectrum is actually a continuum, the rainbow is perceived by the
human eyeThe human eye is an organ which reacts to light for several purposes.As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
(and the eyes of many other
mammalMammals are a class of vertebrate animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair, three middle ear bones used in hearing, and a neocortex region in the brain.Mammals are divided into three main...
s) as discrete bands, due to the finite number of photoreceptor cell types in the eye.
Roy G. Biv is a
mnemonicA mnemonic device is a mind memory and/or learning aid. Commonly, mnemonics are verbal—such as a very short poem or a special word used to help a person remember something—but may be visual, kinesthetic or auditory. Mnemonics rely on associations between easy-to-remember constructs which can be...
for the sequence of hues in the
visible spectrumThe visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nm...
, in
rainbowA rainbow is an optical and meteorological phenomenon that causes a spectrum of light to appear in the sky when the Sun shines onto droplets of moisture in the Earth's atmosphere...
s, and in order from longest to shortest wavelength:
- Red
Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked human eye...
- Orange
- Yellow
Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–580 nm is yellow, as is light with a suitable mixture of somewhat longer and shorter wavelengths...
- Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
- Blue
Blue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
- Indigo
- Violet
As the name of a color, violet is used in two senses: first, referring to the color of light at the short-wavelength end of the visible spectrum, approximately 380–420 nm when indigo is recognized as a distinct color, or more commonly 380–450 nm...
Another way to remember it is:
Richard
Of
York
Gave
Battle
In
Vain.
The colors are arranged in the order of decreasing
wavelengthIn physics, the wavelength of a sinusoidal wave is the spatial period of the wave – the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
s, with red being 650 nm and violet being about 400 nm.
History
Although the spectrum is actually a continuum, the rainbow is perceived by the
human eyeThe human eye is an organ which reacts to light for several purposes.As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
(and the eyes of many other
mammalMammals are a class of vertebrate animals whose females are characterized by the possession of mammary glands while both males and females are characterized by sweat glands, hair, three middle ear bones used in hearing, and a neocortex region in the brain.Mammals are divided into three main...
s) as discrete bands, due to the finite number of photoreceptor cell types in the eye. Inclusion of the color
indigoIndigo is the color on the electromagnetic spectrum between about 420 and 450 nm in wavelength, placing it between blue and violet. Although traditionally considered one of seven divisions of the optical spectrum, modern color scientists do not usually recognize indigo as a separate division and...
is attributed to
Isaac NewtonSir Isaac Newton FRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian who is perceived and considered by a substantial number of scholars and the general public as one of the most influential men in history...
, who wanted the number of colors in his spectrum to come out to seven to match the number of days in the week, the number of notes in the
major scaleIn music theory, the major scale or Ionian scale is one of the diatonic scales. It is made up of seven distinct notes, plus an eighth which duplicates the first an octave higher. In solfege these notes correspond to the syllables "Do, Re, Mi, Fa, Sol, La, Ti, "...
, and the number of known planets. He originally (1672) named only
five primary colors: red, yellow, green, blue, and violet; only later did he introduce orange, and indigo.
The
Munsell color systemIn colorimetry, the Munsell color system is a color space that specifies colors based on three color dimensions: hue, value , and chroma . It was created by Professor Albert H...
, the first formal color notation system (1905), names only five "principal hues":
redRed is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye, in the wavelength range of roughly 630–740 nm. Longer wavelengths than this are called infrared , and cannot be seen by the naked human eye...
,
yellowYellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–580 nm is yellow, as is light with a suitable mixture of somewhat longer and shorter wavelengths...
,
greenGreen is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
,
blueBlue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440–490 nm. It is considered one of the additive primary colours. On the HSV Colour Wheel, the complement of blue is yellow; that is, a colour corresponding to an equal...
, and
purplePurple is a general term used in English for the range of shades of color occurring between red and blue. In additive light combinations it occurs by mixing the primary colors red and blue in varying proportions...
(although note that Munsell's purple is not a
spectral hueA spectral color is a color that is evoked by a single wavelength of light in the visible spectrum, or by a relatively narrow band of wavelengths...
).
The meaningless but speakable word ROYGBIV is also used as a mnemonic for the spectral colors, as is its slightly less euphonious reverse VIBGYOR.
Another traditional mnemonic device has been to turn the seven initial letters of the spectral colors into a sentence. In
EnglandEngland is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west and the North Sea to the east, with the English Channel to the south separating it from continental...
the most common is
"Richard Of York Gave Battle In Vain". The mnemonic is said to refer to the defeat and death of
Richard, Duke of YorkRichard Plantagenet, 3rd Duke of York was a leading English magnate, descended from King Edward III. He inherited great estates, and served in various offices of state in France at the end of the Hundred Years' War, and in England, ultimately governing the country as Lord Protector during Henry...
at the
Battle of WakefieldThe Battle of Wakefield took place at Wakefield, in West Yorkshire, on 30 December 1460. It was one of the major battles of the Wars of the Roses...
. In order to avoid reference to this defeat, those from Yorkshire developed the alternative
"Rowntrees of York Gave Best in Value". Alternately, the Biblically inspired "
Read
Out
Your
Good
Book
In
Verse" may be used.