Though the work does have overlaps, being a designer and being an art director are different roles that require different skill and mindsets. I've worked in both design and advertising agencies and I've seen for myself that the best graphic designers are not always great art directors. Likewise top art directors are not always too clever on the design front. Don't make the mistake of thinking that because they both work with images they do the same job. They don't.
Graphic Design is all about execution and while designers often need to have strong conceptual flair, they are often more hands-on than art directors. They are the ones who are constantly pushing and pulling the various visual elements to get the perfect balance, making small adjustments here and there and asking questions like "do these colours match? Is the line-length comfortable? Is this photo in focus? Does the typographic hierarchy work? Is this composition balanced?" And of course, "Can I make the logo smaller?"
A job spec for a designer would be something like this:
Ability to follow a brief.
Excellent attention to detail.
Strong Strong communication skills, literate and able to spot typos.
Ability to work under pressure and deliver within tight deadlines.
Self-motivated with ability to work alone and as part of a team.
Confident and resilient to constructive criticism.
Art Direction on the other hand involves more thinking. First and foremost it's about cracking the big idea and then finding a way to express that idea or give it some kind of visual language that will draw people in. If you want to become an art director, you need to understand the overall scope of the project and be skilled at coming up with concepts that reflect and adhere to the creative strategy.
It's actually more of a management role because art directors must be able to direct photographers, illustrators, designers and anyone else involved in achieving the art director's vision. In their excellent book "Art Direction Explained, At Last!", Steven Heller and Veronique Vienne distill the job of an art director: The first rule is making decisions, the second is making the right decisions.
A job spec for an art director would be something like this:
Must be able to concept, direct, and produce work.
Think beyond a design or concept to the broader business goals.
Present well, both internally and in client-facing meetings.
Take feedback and critique from all levels, from account staff to creative director to client.
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