Acting as an equilibrium against perfectionism in accuracy artistic license is employed to make a more satisfying cover and give the artist some freedom in interpreting the chosen scene. Outside of a photograph or a video (which may not be what they seem) all tales, histories, stories, novels, poems, and anecdotes are imagined as they are told and retold by each person. When darkness came upon the land during the Crucifixion of Christ was there an orange sliver of light on the horizon, a bluish cast to the sky, or a morbid gray pall across the scene? Before Gollum made an appearance in the LOTR movies what did he look like? Does Lancelot have a mustache? Each artist given the task of illustrating the Crucifixion, Gollum or Lancelot could answer these questions in his art, but there is no definitive answer even if a character is described by an author like Gollum only guideposts along the way.
The freedom of the artist with this license distinguishes each work from another’s and can keep a subject which has been drawn ten thousand times before fresh to the viewer, full of depth, passion, and life. One only needs to look at the myriad of versions of the Madonna and Child from the Italian Renaissance alone to see how artists can take a single subject and like a fertile field of wild flowers paint the world with beautiful variety.
This license goes beyond variety and allows for artists to reimagine a scene for better composition, drama and simple marketing. In the story the priestess of the sun god may have been behind the noble knight fighting the creature of darkness, but for the cover she is kneeling in front of him and below as she bestows her healing power to keep his keen edged sword in the battle. There’s no mention of her robes being torn and a shapely leg showing through, or that her tunic is turned down revealing her ample and pale cleavage either, but no words in the scene state those things did not happen. How many romance novels have the Pirate-King’s flimsy shirt torn open revealing the chest of a Greek god, or fantasy novels with the buxom female in impracticable, and non-existent chainmail wielding swords larger than described in the book itself? Sci-fi covers routinely have two ships firing a broadside of guns at each other like the age of sail when in reality space battles would likely be slowly fought over incredible distances and even the story itself has the beams fired from a thousand miles away.
As the pendulum swings towards artistic license, it can go too far and limits must be imposed. Even if Supergirl is not incorrectly shown as Superboy her hair cannot be brunette, Mary cannot be a green skinned alien from Zebulon V even if she is a virgin holding an alien baby assuming the image goes into a Cathedral dedicated to the historical Mary, and the darkness at the Crucifixion cannot be caused by a Cthulhu blocking out the sun if it isn’t a story about a Cthulhu showing up at the Crucifixion. Another limit is the once again the tone of the cover must fit the genre and this applies to license just the same as accuracy.
I believe the artist, author, and publisher can resolve this tension by finding a point in which accuracy and license can meet and give the best cover possible. In the above diagram based loosely upon the Laffer Curve there is a point in which the two opposing forces meet with maximum effect. The difficult task is finding this point of which I’m afraid there is no perfect formula. Like most creative endeavors it is much more perspiration than inspiration joined with communication and a commitment to producing the best possible work. United with the other particulars which make good artwork in general I believe that all parties involved will know they have the right cover the closer they get to this maximizing point. Artwork suddenly becomes a book cover when this point is reflected in the finished product and the book and publishing world is a little bit better for this happy meeting.