Literature about etching and institutional rhetoric not only established the intellectual and professional credentials of the etcher but also described the advantages of the distinctive technical processes of etching for the production of spontaneous and creative work, as we have seen in Chapters 1 and 2. The constraints which these technical processes placed on the production of etchings, and the fact that the etching was both an object produced as a multiple and capable of minute variation, were equally valued by print collectors, whose activities established it as a collectable luxury commodity. The key element in this positioning of the etching as a commodity was the system of 'states' and 'proofs' used to describe and assign value to the etching at different stages of its production. This system proved to be a site of conflict between etchers and collectors who had very different ideas of how value should be assigned to the etching.