The other day I visited the excellent exhibition of paintings by John Martin at the Tate Britain. I have been a fan of Martin's work since my teens, but despite some cursory reading knew little of his background or career. Although the epic biblical scenes for which he is most famous drew accusations of bombastic popularism in his time, they are truly stunning. The canvasses themselves are huge (often ten or twelve feet across) and inspire the intended awe. He was trained as a craftsman and spent his early years painting decorative scenes on ceramics. Although this served admirably as training for his later work as a grand salon painter, it also hampered his progress. The particular techniques he developed for ceramics were not regarded as 'painterly' enough by the establishment and so the approval and election to the the Royal Academy eluded him.
I was surprised to learn that Martin's work suffered from the very modern issue of copyright even during his lifetime. Several of his paintings proved so popular after Martin had sold them (and the subsequent owners had made large sums promoting the pictures at salon exhibitions) he painted a second version so he could tour them himself and receive the profits. His patrons not unreasonably cried foul and there were legal wranglings. This fact might account for the way the subsequent copies Martin crafted often differed from the originals in aspect ratio, which strikes the viewer as quite strange when one sees both versions hanging side-by-side.
Martin is also famous for his wonderful mezzotint engravings, particularly of Paradise Lost and the Bible. He tried with varying success to make money from these but copyright and copying dogged this endeavour too. He strived to make quality prints but when this floundered he sold the plates and it was actually the cheaper versions produced by subsequent publishers which sold better. Also, other engravers copied his work and so a black market of sorts eroded his sales.
Martin's reputation as a painter diminished in the early 20th century to the extent that when The Destruction of Pompeii and Herculaneum was badly damaged by a (aptly epic) flood in 1928 it was not repaired. Tate conservationists have done a wonderful job of restoring the canvas and even reconstructing a large missing portion. They were able to do this because, ironically, good photographic records existed of the work pre-flood. Thus the phenomena of the copy (in this case photographic) which was so much a part of Martin's career has helped save one of his best works.