HunterLab Colorimetric Spectrophotometers Versus Analytical UV-VIS Spectrophotometers

Often workers in analytical laboratories ask what the difference is between their UV-VIS spectrophotometer and their HunterLab colorimetric spectrophotometer. This Applications Note details the differences between them and why both types might be needed in a single laboratory.

A HunterLab spectrophotometer is a visible spectrophotometer, meaning that it measures light in the visible range of the electromagnetic spectrum (approximately 400-700 nm). As designed, its purpose is to quantify color as humans see it, and we can only see within this visible area. A UV-VIS spectrophotometer measures over a larger wavelength span, which includes the visible region of the spectrum and the ultraviolet region, and sometimes extends into the ultraviolet.

HunterLab spectrophotometers quantify the human perception of an item's color, a psychophysical phenomenon, while the focus of UV-VIS measurements is correlation to spectral data, a purely physical property.

A HunterLab spectrophotometer attempts to answer the question "What color is it?" It only needs to measure every 5-10 nm to answer this question. A UV-VIS spectrophotometer normally answers a question like "How much of my chemical of interest is in it?" Because of this purpose, it will normally measure every 2 nm or less.

While the intended purpose of a HunterLab spectrophotometer is to quantify color, it can also report spectral reflectance and/or transmittance data at 5 or 10 nm intervals.