HOW SPECTROPHOTOMETER WORKS?

In order to accurately understand how does a spectrophotometer work, the first thing you need to understand is how color functions. This is a wide topic, so for this article, let’s have a fast overview. Color consists of wavelengths of light and we can split it into six categories:
•    X-rays
•    Ultraviolet
•    Visible light
•    Infrared
•    Microwaves
•    Radio waves
You can see from the list above that visible light is somewhere in between other categories, and this is what the spectrophotometer analyzes to create the desired color. The visible light spectrum is composed of red, orange, yellow, green, blue, indigo and violet. These are seven colors of which all the different colors we can see with the naked eye are created. Now don’t get confused with the absence of black and white. Black is the actually present when there is no color, and white is made up of all of these colors combined. A spectrophotometer is, in fact, a relatively simple device. The primary parts of a spectrophotometer are:
•    Source of illumination
•    Interference filters that are powered by stepper motor
•    Detector (also known as photodiode)
•    Readout device
Since it’s comprised of the greater part of the hues in the noticeable range, white light is the enlightenment source utilized as a part of a spectrophotometer, as a tungsten knob or in more propelled models, a Light Emitting Diode (LED). A clasp situated on the outside of the machine holds the paint test to be coordinated, and white light is overflowed onto the example. This light is reflected off the specimen once more into the machine and onto a little wheel. The wheel is a profoundly effective shading analyzer, comprising of various obstruction channels and controlled by a stepper engine, which is known for its accuracy. 
Unmistakable light is measured in nanometers, which is a modest unit of estimation in the metric framework, equivalent to one-billionth of a meter. Every channel is customized to permit a particular wavelength of light to go through it, and every wavelength is inside a specific scope of nanometers. The noticeable light range ranges from the reds at 400 nm to the blues in the 700nm territory, and the most productive wheels have channels that handle interims of 10 nm each.