Given the number of successful writer-illustrators out there, it’s perhaps unsurprising that writing and illustrating are so often treated as concurrent skills when, in fact, they are quite different and people skilled at one may have no talent at all for the other. Authors, I think, tend to respect the time and skill that goes into illustrative art. “I could never do that” is a common sentiment, and authors who are perfectly competent illustrators are often diffident about their own skills. Witness Tolkien: although he produced quite a few ink and watercolor illustrations of The Hobbit and The Lord of the Rings, such as the gorgeous rendition of Smaug shown here, he never felt himself equal to the task of illustrating his own works, and would downplay his skill or refuse point-blank when publishers expressed interest in seeing more of his art. Some comments regarding the schedule for The Lord of the Rings are typical:
I should have no time or energy for illustration. I never could draw, and the half-baked intimations of it seem wholly to have left me. (letter to C. A. Furth, February 1939)
Thus, although many early editions of The Hobbit contained his illustrations, his work as an illustrator still languishes in obscurity, and it is later illustrators such as the Alan Lee–and now, of course, Peter Jackson–who visually define his work.
Illustrators are another matter entirely. They have the less common skill set; they are in far greater demand; their part of the process is inevitably the more time-consuming. Therefore, I expect illustrators to more commonly decide to branch out and become writers.
This rarely, if ever, goes well. I’m not counting writer-illustrators who made their big breaks in illustration but had always practiced both skills (eg, Beatrix Potter), but rather illustrators with a purely artistic background who took up writing later. It turns out that writing requires its own distinct skill set, one which people who have not previously dabbled in writing are unlikely to have.
As an example, I present the Hildebrandt brothers’ novel Urshurak. The Hildebrandts are excellent illustrators who brought their signature hypersaturated realism to The Lord of the Rings and its descendant, The Sword of Shannara, in the 1970s. In 1979, presumably inspired by the success of the Tolkien-knockoff market, they produced their own novel. Although lushly illustrated, it works very poorly as a novel. The Hildebrandts recognize all the elements that go into a fantasy novel, but they don’t seem able to put them together into a coherent, satisfying whole. It’s exactly the mistake you would expect a pair of illustrators to make: Interpreting a novel as a series of cool ideas and disregarding the importance of the themes and underpinnings necessary to tie it all together.
Consider this plate from Urshurak, depicting Gandalf clone Elgan and his race-swapped counterpart, Shandar (do you even need to ask whether there are two wizards so that one can die later?). The technical skill, of course, is very good; the composition is nice. It would make a good fantasy poster that you could imagine on the wall of a dorm room in the 70s. But what kind of contrivance would a book require to actually make this scene happen? Here it is:
When [Elgan] looked up, Shandar was watching him, his left hand raised, the palm toward Elgan. The two ancient beings moved toward one another slowly. Elgan returned Shandar’s sign of peace, he felt the sorcerer’s serenity within him…They came together, their upraised hands inches apart in a transference of the energies of their complete love and acceptance. (Urshurak pp. 123-124)
Okay, so it’s exactly what it looks like: The two wizards are walking towards each other with their hands raised for no reason. The Hildebrandts wanted this picture, so here it is, regardless of whether it makes sense and whether this is the sort of thing that actual people would ever actually do.
Of course even an illustrator with no experience as a writer could successfully become one, but it would require practice, training, and a lot of feedback, with a careful eye for “illustrative” mistakes like the above. Let’s have some respect for writers: Storytelling is a skill in itself, and one not everyone has.