Climatic standards for museums have been established on the basis of empirical data gathered only in England or on scientific data referring mainly to new materials, which are hardly comparable to museum objects. A brief analysis of how such standards are defined, and a comparison of the figure proposed in the literature point up contradictions, and a lack of scientific accuracy. Meanwhile, until research has developed further, another approach to standards is proposed. It is based on the fact that the temperature is of minor importance, and on the principle that the ideal relative humidity is that to which the object has become accustomed in the past. As a result, it is essential to know the object's curriculum vitae in order to determine the proper relative humidity. -- AATA