"A grey day provides the best light" - Leonardo da Vinci
Can you picture life without colour? Recognizing colours and assigning meaning to them has become second nature, but how did we get started with creating a palette of these beautiful colours? Over 40,000 years ago, artists used a unique combination of chalk, soil, animal fat, and burnt charcoal to create the earliest known record of pigments. This resulted in a foundation of five colours that would serve as the basis of art for years to come: black, white, red, yellow, and brown. But this is quite incomplete, rainbows used to have only five colours until 1704, when Sir Isaac Newton added orange and indigo to the list simply because he liked the ostensibly mystical properties of the number seven.
There are, in fact, no pure colours in a rainbow; they all blend into one continuous spectrum. However, we have settled on 7 and used little rhymes to remember them since Newton. American children may learn 'Roy G Biv', whereas the British settle with 'Richard Of York Gave Battle In Vain' - red, orange, yellow, green, blue, indigo, and violet, well too many coloured stories.
What exactly are colours?
Aristotle devised the first known theory of colour, believing that it was brought from heaven by God in the form of celestial rays of light. He proposed that all colours originated from white and black. The colour concepts espoused by Aristotle were generally held for nearly 2000 years, until being supplanted by Newton's.
As illustrated in “The Book of Opticks” by Sir Isaac Newton,
“if the Sun’s Light consisted of but one sort of Rays, there would be but one Colour in the whole world”
Newton demonstrated that colour is a quality of light with the help of a prism experiment, which divided white light into a range of colours known as the spectrum, and that the recombination of these spectral colours recreated this white light.
But he realized that colours other than those in the spectral sequence do exist, leading him to note,
“ All the colours in the universe which are made by light, and depend not on the power of imagination, are either the colours of spectral colours, or compounded of these”.
Though precisely, colours can be also specified by their hue, saturation and brightness. These three attributes are sufficient to distinguish them from all other perceived colours.
How do we see colours?
Electromagnetic wavelengths are called visible light. The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. This given beam of light lying in the visible spectrum has specific wavelengths, frequencies & energy associated with it. Frequency is defined as the number of waves crossing a fixed point in space in a unit of time, which is generally denoted in Hertz (Hz). Wavelength is the distance between the corresponding points of two successive waves and is commonly given in meters (m). The energy of a light beam is comparable to that of a minuscule particle travelling at the speed of light, except that no particle with a rest mass could move at such a speed. Wavelengths of light ranging from about 400nm to 700nm define the visible region. At shorter wavelengths, the electromagnetic spectrum extends to the UV and continues till X-rays & Gamma rays, and higher wavelengths extend till AM and shortwaves.
The colours of the rainbow can vary over history, and when we look into the perspectives and experiences of these colours, we see considerable differences. Colour interpretation is vital and has grown via nurturing rather than the natural perception of a specific colour. Colour is one of the most influential features of our lives. The colours we surround ourselves with can have a huge effect on our daily lives.
- Samarth Sharma Amit
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