This paper questions the notion of good contexts for translators and describes an experiment which tests the usefulness of two specific kinds of contexts in a translation task, namely (1) contexts that provide conceptual information about a term, and (2) contexts that provide linguistic information about the collocational profile of this term. In the experiment, trainee translators are asked to use several types of resources, including a set of pre-annotated contexts of various types, and to identify the contexts that they consider to be the most relevant for their task. We present the first results of this experiment, which confirm our general assumption about the usefulness of such rich contexts and indicate some differences regarding the use of contexts in the source and target language. This study takes place in the CRISTAL project whose aim is to retrieve from bilingual comparable corpora the contexts that are the most relevant for translation and to provide them to users through a CAT tool.