I'm always questioning how far to take metaphor in design conceptualization. I got very excited about helping Sun Microsystems announce one of their Java products earlier in my career. I love coffee. Any chance to sketch, research and think about the mechanics behind this happiness was just find with me. I sat in a cafe and sketched this old fashioned coffee roaster live. I couldn't capture the gold reflected polished brass. But it didn't matter. I just wanted to know one thing ... how to map the functional aesthetic of the coffee roaster to the educational elements of the product launch. If you study this closely, my first draft of mapping this logic fails greatly. Too wide of a gap and not correct in terms of action. For instance, registration is the final step. The cooling of the beans in metaphorical terms implies that customers will be done with the process, yes -- but it also leaves them suspended. Cooling. When in fact, registration is just beginning.
It flopped. But metaphor is an engaging start point. And if it's important to go all the way, there are several options. Animation, or street films to open up the concept and expand the business meaning. But often what happens due to budget constraints and priorities is the metaphor gets killed or someone takes the image and uses it as not intended.
Metaphor has inherent limitations. There's a black and white quality to it. On a different project I accessed old images of the London Tube to create an advertorial intranet metaphor with subway transitions as the underpinning of action. It worked perfectly. There was zero confusion. This rarely happens. As for my lil' coffee roaster, it will be well placed in a book I'm working on now "The Traveling Bean: Coffee Tribes Around the Globe" -- it all gets recycled somehow.
Even though metaphor is limited in use, I will never stop using it as a creative thinking prompt. You never know where it might go.