Many people ask me, "What is NIR?". This is what I tell them...
Near Infrared Reflectance Spectroscopy (NIRS) is a spectroscopic method utilising the near infrared region of the electromagnetic spectrum which ranges from 800 to 2500 nanometers (nm).
Ok, so that might not mean a lot to many people. Let me try to explain it more simply!
When light is shone on a material it may be absorbed or reflected. Different materials interact with light in different ways, absorbing and reflecting different frequencies of light.
It is this process which gives rise to the colour of a material. Now you know why roses are red (well, it is nearly Valentines Day!) - the green and blue light is absorbed by the rose petals and only the red light is reflected.
Spectroscopy is the study of how different materials absorb light, and how this can be used to identify materials based on which frequencies of light they absorb. The more of a particular material you have, the more light will be absorbed.
Next time I'll explain more about these absorbances and how they relate to NIR.