Page 106 - Graphic Design and Print Production Fundamentals

94 Chapter 4. Colour Management in the Graphic Technologies
Spectrophotometre

Spectrophotometres measure slices of the spectrum to produce a spectral ‘map’ of the light reflected
back from a sample. Spectrophotometers are typically more expensive than densitometers and
colorimeters but are employed because they can more accurately do the jobs of both devices. They work
by recording the light at specific wavelengths over the wavelength range of visible light, and then by
converting this spectral data to colorimetric and densitometric values.

While we are talking about measuring spectral values, it is important to note that we do not depend on
identical spectral values to achieve matching colour experiences. Different spectral values can trigger the
same volume of colour signals in our optic system and lead to matching colour perception. In fact, we
depend on this phenomenon in graphic production in order for proofing devices to simulate the colour
output of a printing press or for any two devices to be colour aligned. The ability of the CMYK (cyan,
magenta, yellow, black) process colour set to mimic most of the colours in the world is also based on the
fact that we can achieve a colorimetric match without having identical spectral values.