In this work we present four contributions (Chapters 2, 5, 6, and 7) which have been published in international magazines and some other in proceedings with peer review. One of them has been accredited in agreement with a norm by international recognized organisms as the mexican entity of accreditation (ema). They all have been put in practice in the solution of industry problems with great results. In Chapter 1, the basic theory of colour is presented as a psycho-physical magnitude which is determined by the spectrum of the light source. Also, the human eye response to the incident flux and the final information decodification by the brain. Although this Chapter is just a review that explains the behaviour and the quantification of light sources as well as the human observer. This review is of great importance in the development of this work, because is the theoretical support that make us understand and apply the proposals presented in Chapters 2, 3 , 5, 6, and 7 to our needs. The colour by its nature is a phenomenon that involves physical aspects as well as psychological and physiological ones. Because of theses different measurement and classification systems developed to specify and quantify it have to consider them. The visual evaluation of colour, more on, the evaluation of colour differences is perhaps the most common practice and at the same time the most critical one. These evaluations are involved in the generation processes and the high quality control of colour, here arises the need of known the discrimination capacity if the observers who evaluate. In this sense, there has been a development of different types of test to qualify the capacity of human beings to discard one or some of the colour attributes (i.e., hue, chroma, value). When these tests are applied to evaluate the observer capacities, it must be taken into account some factors; the duration of the test, the number of observations, level of luminosity, etc. In Chapter 2, the obtained results of the test, The Farnsworth Munsell 100 Hue Test, are analyzed. This test was applied to 129 Mexican observers. It offers a simple method to evaluate the discrimination of hue with daylight under the same conditions. The observers were men and women, who participate in the colorimetric courses, which are offered at INAOE as part of a continuous training.