Ruskin acquired his first set of the Liber Studiorum from the artist himself in 1845, after Turner had had the plates reprinted specially for the purpose. But Ruskin was dissatisfied with these reprints because the plates were badly worn, and for many years he continued to collect better impressions and proofs, as well as proof impressions of the pure etchings. (See Davis, The 'dark clue' and the Law of Help, pp. 34-36.)