The publication is the introduction to a series of papers concerned with the objective evaluation of colour changes of the slon to which we devoted attention for ahnost 30 years. The authors outline the history of different subjective, photographic and photometric methods. The best evaluations are obtained nowadays by chromameters (colorimeters), instruments for assessment of erythema and dermaspectrometers and spectrophoto(fluori)meters. In the section on chromatometry the authors discuss the physical basis of estimations by the CIE system, the principle of estimation, standardization and reproducibility of the procedure and they mention the present state of equipment and possibilities. The authors mention in more detail instrnments such as MicroColor, Dermaspectrometer and ErythemMeter. They emphasize the importance of the erythema and melanin index. In the hnal part of the paper the authors summarize possibilities how to use chromatometry in practice. This involves in particular evaluation of erythhmms and their intensity, pigmentation, ageing of slon, effect of treatment (psoriasis, atopy), side-effects of drng (e.g. local corticosteroids) protective UV procedures, detergents, epicutaneous tests etc.

        Key words: chromametry - colorimetry - reflex, remittance, reflectance spectrophotometry of the slon - objectivization of slon colour