Despite colour becoming ever more important not to mention ubiquitous in nearly every walk of life, understanding colour is still problematic for many.
Classified as a "Sensory Science" it does not behave like a "Normal" physical property of an object. Particularly when talking colour in Quality Control, the tendency to manage by absolute numbers is still strong, while ignoring the fact that these numbers "Lie".
There are about 14 conditions that need to be identical from one measurement to another if absolute numbers are to be half believed, but unless you are predicting colour (CCM) it makes much more sense to look at the Colour Difference values.
Trials show that when measuring the same group of colours with different colour instruments, from different suppliers with different settings say in the CIE L*a*b colour space, the absolute values vary, but the colour difference trends remain remarkably similar.
This complicates long distance measurements i.e sharing colour between say a manufacturer in China and an assembly plant in South Africa. Here, a software TEMPLATE is very helpful to manage the 14 conditions, as well as Konica Minolta instruments, which have a very high level of inter instrument agreement under the same conditions. Mail firstname.lastname@example.org for more, or see http://www.cyberchromeusa.com/Color-QC-and-Matching-Blog/?Tag=OnColor for more interesting views on colour