One of the most frequent questions I get from young or aspiring illustrators is about having multiple styles in a portfolio. While it’s true that you should have a consistent style, it doesn’t necessarily have to be limited to a single one if you know what you’re doing.
Style Vs. Technique
The first thing I’d suggest is considering whether you’re confusing style with technique. Style is about how you solve problems, the visual language you speak, and the overall aesthetic qualities of your work. Technique is how you bring those things to life. In the hands of a pro, it doesn’t matter if it’s an oil painting, a woodcut, or a Photoshop masterpiece, they’ll all look as if they came from the same mind. If that’s your situation, quit sweating about it and get back to work. If, however, the art looks like it’s from a few completely different people that may be a problem. Don’t fret, though. There are ways to get past that, including:
Multiple styles may not count as a strike against you if each style is fully developed and equally awesome. They can’t look like one-off experiments, but must be treated and managed like fully-realized identities. Anything less and it’s confusing and scary to an art director.
Depending on how wildly disparate your multiple illustration styles are, you may want to separate them in your portfolio. Organization can play a big part in helping people contextualize your work and not be frightened off.
You may also want to promote the multiple styles separately. Instead of jamming everything onto a promo card sent to all the same A.D.s, create specific campaigns for each style.
Let the market sort it out
Of course, even if you do master the art of illustrating in multiple styles, they may not all be successful. In the end, the market will help determine which one(s) succeed and which should be left to your personal Tumblr page. As time goes on, you’ll naturally settle into the style you work most frequently in and the problem won’t be an issue anymore. If, however, you find yourself equally successful in multiple styles, well, good for you—you’re doubly (triply?) marketable!