The visible light spectrum for human vision is relatively narrow, spanning only from around 380 nm (violet) to about 750 nm (red). However, the whole electromagnetic spectrum covers a much larger range, spanning beyond ultraviolet and infrared to include x-rays, gamma waves, microwave and radio waves.

RGB cameras will normally only cover the visible light spectrum. However there are more specialized cameras that can capture parts of the infrared (NIR, SWIR, …) and/or ultraviolet spectrums as well (and even x-rays). The “invisible” parts of the spectrum can be quite useful for detecting features that are generally related to the chemical composition of the objects.