The impression of colours has always been instinctive first, psychological second. In fact, colours have long dominated humanity’s perception of what is repulsive and attractive.
While white has always been associated with royalty and nobility, black, on the other hand has always been associated with death and sin. It is a colour that denotes secrecy and mystery, concealing literally anything and everything.
Why are things black?
Goethe and Newton were the first two people to study the science behind colours. However, they had very distinct approaches to their study. For Goethe, he took a more physiological and experiential approach. At the same time, Newton theorises colour through scientific experimentations in a lab.
Light, a form of electromagnetic wave, is part of a group of different wavelengths. However, only a specific range of wavelength is visible to our eyes. This visible range can be divided into the seven colour spectrums that Newton observed.
Objects absorb and reflect these wavelengths. For example, a blue colour shirt will appear blue because the molecules and atoms of the dye will absorb the other wavelengths, reflecting only blue. What, then, does it say about white and black or light and dark?
Basically, they are the complete opposite of one another. Where black is the complete absorption of every colour wavelength, white is the complete reflection of every colour wavelength. Hence, black is not just an absence of light but a carefully created mixture of pigments, as Goethe discovered. The absorption of light usually results in the manifestation of heat. This is why it is recommended not to dress in black on a hot day. However, while brighter hues of colours can be attributed to the intertwining and reflection of several wavelengths, what about various shades of black?
How black can reflect light?
The origin of the word “black” can be traced back to an old English word of Germanic origin, “ blæc”, which means dark, as well as a Proto-Indo-European word “bhleg”, which means flash, shine, or gleam. Yet, we know that black absorbs all colour wavelengths. How, then, does some black object somehow manage to reflect light? This occurrence boils down to two primary factors: the surface of the object and the amount of incident light.
In the absence of adequate lighting, even blue can be perceived as black. Additionally, the difference between glossy and matte black can be traced back to the amount of incident light that it absorbs and reflect, which is significantly affected by the object’s surface.
Only truly black objects absorb light completely without reflecting any. An example would be a black hole which absorbs anything and everything in its path, even light. On top of that, minute surface irregularities will allow a small amount of light to reflect.
For example, irregular or rough surfaces allow for diffuse reflection, scattering light in every direction. The scattered nature of such reflection results in the object appearing darker or more matte. On the other hand, smooth surfaces allow for specular reflection, which is a more concentrated and narrower reflection of light. The concentrated nature of such reflection results in the object appearing lighter or glossier.
In 2014, a UK nanotech firm developed the world’s first blackest material, called Vantablack. It is known to be so black that it reflects only 0.045 per cent of incident light.
The science behind black is indeed an interesting study. While black generally absorbs every colour wavelength, it can still be affected by the surface of the object and the amount of incident light. With that being said, should you be interested to know more about light wavelengths and how they play a part in physics, then consider Physics Tuition. Our classes are not only engaging but also results-driven. Contact us to find out more!