The article ‘A vision of Middle-earth‘ by Paul Tankard, written for The Times Literary Supplement, is available to read online. The article, published in September 2012, provides information about Mary Fairburn, the artist for the 2015 Tolkien Calendar.
The article chronicles J.R.R. Tolkien’s communications with Mary Fairburn as well as the insights into his view of her work. It quotes from a number of letters between Tolkien and Fairburn. The article concludes:
Mary Fairburn’s images are a particularly significant response to The Lord of the Rings, and the artist’s correspondence with Tolkien makes them uniquely interesting and valuable. […] When he complimented her on her “attention to the text”, and told her that her paintings conformed to his own “mental vision” and were causing him to reconsider his view that the book should not be illustrated, this was more than gratuitous flattery. And his reiterated request to see more of her paintings, and in particular his “private offer of purchase” and “gift” of £50, were far more than mild encouragement. Her paintings were seen and approved by him, not simply as fine paintings of his imaginary land, but as sympathetic and illuminating illustrations of his book, that – had circumstances been different – he might have been prepared to see printed alongside his text. They thus offer a unique insight into the author’s own vision of The Lord of the Rings.
You can read the full article on the TLS website.