With the development of the media and with the competition of the marketing, the colour became a differenttial, such for the recognition of a commercial mark as for the sensation of a good product (example: oranges, apples, French fries, soft drinks). In this context we observe the need of expressing properly products colour. Industries and companies must assure the quality of their products and services. Among the several items to be controlled we can remark the quality of the colour product and consequently the appropriate perception of this for the consumer. In fact, in many cases we notice a great difference between the projected colours, the produced ones and the colours perceived by the final users. The industry should be capable to assist to the consumers' expectations guaranteeing the constancy of the colour of their products. This subject affects several industrial sectors like: automobiles, manufacturing, textile, urban and domestic furniture, food, design, scenic and graphic arts, paints, cosmetics, etc. The proposal of this article is present a methodology to study how the human being perceives and express the characteristic of product colours in realistic conditions. This work deals with different colour hues, submitted to different lighting. Acquiring those quantitative measurements, it will be possible to reproduce human-like colour perception of commercial product. In this context, this paper presents some results of a research in colour vision. We consider specially the colour perception in different illuminations. The presented results may help designers to adjust their product colour according to human colour difference perception.