On what does the color of light depend

So by these we can say that colour of light depends upon wavelength and frequency both. The color of the light is determined by the frequency of the light wave. Red, is lowest, frequency and violet is the highest. First of all, scientists have determined that in the lab we can see about 1, levels of dark-light and about levels each of red-green and yellow-blue. White light appears to be white since it consists of each and every colour on the visible spectrum.

The order of colours is like this, violet, indigo, blue, green, yellow, orange and red. The retina of our eyes contains two types of photoreceptors — rods and cones. The cones detect colour. The rods only let us see things in black, white and grey. Our cones only work when the light is bright enough, but not when light is very dim.

This is why things look grey and we cannot see colours at night when the light is dim. There are three types of cones in the human eye that are sensitive to short S , medium M and long L wavelengths of light in the visible spectrum. These cones have traditionally been known as blue-sensitive, green-sensitive and red-sensitive, but as each cone is actually responsive to a range of wavelengths, the S, M and L labels are more accepted now. These three types of colour receptor allow the brain to perceive signals from the retina as different colours.

Some estimate that humans are able to distinguish about 10 million colours. The primary colours of light are red, green and blue. Mixing these colours in different proportions can make all the colours of the light we see.

This is how TV and computer screens work. If you look at a screen with a magnifying glass you will be able to see that only these three colours are being used.

For example, red and green lights are used to make our brain perceive the image as yellow. When coloured lights are mixed together, it is called additive mixing. Red, green and blue are the primary colours for additive mixing. If all of these colours of light are shone onto a screen at the same time, you will see white. This is different when you are mixing paints. Each colour of paint is absorbing certain colours and reflecting others.

Each time another colour of paint is mixed in, there are more colours absorbed and less are reflected. The primary colours for adding paints or dyes, such as for a computer printer, are yellow, magenta and cyan. It always seems to look dark compared to other sources at equal intensity. Somewhere between THz and THz the world goes dark again. The simple named colors are mostly monosyllabic English words — red , green, brown, black, white, gray.

Brevity indicates an Old English Anglo-Saxon origin. Monosyllabic words are generally the oldest words in the English language — head, eye, nose, foot, cat, dog, cow, eat, drink, man, wife, house, sleep, rain, snow, sword, sheath, God…. These words go back more than fifteen centuries.

Yellow, purple, and blue are exceptions to the one-syllable-equals-English rule. Yellow and purple are Old English color words with two syllables. Some of the names for colors are loan words from French many of which are loan words from other languages. Garage is also an obviously French word. The words violet and orange were the names of plants nouns before they were the names of colors adjectives. Violet came from 14th century French, which came from Latin. Orange came from 16th century French, which came from Italian, which came from Arabic, which came from Persian, which came from Sanskrit.

English arose when three Germanic tribes — Angles, Saxons, and Jutes — migrated from continental Europe to the British Isles in the 5th century. The language they spoke is called Anglo-Saxon or Old English. You would hardly recognize this language if you heard it spoken or saw it written today.

Danes probably have the best chance of understanding spoken Old English, Icelanders the best chance of understanding written Old English.

Do you recognize any of them? In the year , an invasion of French speaking peoples — Normans, Bretons, and French — swept over the British Isles. The Normans had an odd empire if that's even the word for it that included the British Isles, northern France appropriately named Normandy , southern Italy, Sicily, Syria, Cyprus, and Libya. One factor leading to the rise of the Normans in their scattered empire is their ability to quickly integrate themselves into the culture of the peoples they conquered.

For purposes of this discussion, we care about language. When the Normans got to northern France, they started speaking French. In about a hundred years, Anglo-Saxon had mutated into something closer to what we would recognize as English today — neither French nor Anglo-Saxon. Old English became Middle English. The next change in the English language was one of pronunciation — the Great Vowel Shift — This is when silent e and other spelling rules that frustrate both native and second language speakers arose.

The notion of long and short vowels also changed. At one time a long vowel was one that was pronounced for a longer time than a short vowel. Take the words pan and pane. Before the Great Vowel Shift, pan was pronounced "pan" and pane was pronounced "paaaneh" with a literal looong vowel and a non-silent "eh" at the end. Being mostly a change in pronunciation, the rise of Modern English around doesn't affect our discussion of color words.

Movable type printing invented in Germany around is probably more important. Books became relatively plentiful, spelling became standardized, and tracking down the first occurrence of a word became easier.

The Modern English period is when the words orange and indigo were first used to identify colors. There is no physical significance in color names. It's all a matter of culture and culture depends on where you live, what language you speak, and what century it is.

A given wave of light has the same frequency no matter who is viewing it, but the person perceiving the color will call it a word appropriate to their culture. Color discrimination is probably the same for all people in all cultures all people with properly working eyeballs. Did the English see orange or violet before the French told them about it?

Of course they did. What would you call indigo if I showed it to you? Most certainly blue. I don't know anyone who uses the word indigo in everyday conversation. Maybe some painters do. That'd be about it for indigo as far as Modern English speakers were concerned. In some languages blue and indigo are equally significant color words.

Maybe the real question is do we need blue, indigo, and violet? Frequency determines color, but when it comes to light, wavelength is the easier thing to measure. Since wavelength is inversely proportional to frequency the color sequence gets reversed. Wavelength varies with the speed of light, which varies with medium. The speed of light is about 0. If you're trying to understand color, wavelength is just as good as frequency.

We humans who speak English and live at the dawn of the 21st century have identified six wavelength bands in the electromagnetic spectrum as significant enough to warrant a designation with a special name. They are: red, orange, yellow, green, blue, and violet. Where one color ends and another begins is a matter of debate as you will see in the table below. Which brings us to indigo.