Say what you will about Facebook CEO Mark Zuckerberg's hoodie-and-jeans uniform, it works -- and on a number of levels.

The hoodie has stoked controversy in the past, notably when Zuck showed up wearing it to an important Wall Street pitch back in 2012. At the time, critics claimed that there was definitely such a thing as "too casual," and that the Facebook CEO's hoodie made him look like a lackadaisical twenty-something. Of course, that famous hoodie has hardly slowed him down.

In a Town Hall meeting this month, Zuckerberg defended his daily uniform, saying that it comes from "decision fatigue" more than anything else, or the desire to eliminate small-scale decision throughout the day in an effort to improve his ability to focus on bigger decisions. (He also quipped that a hoodie is far better than, say, a unitard or Onesie.) 

But Zuckerberg's particular hoodie, which is always black or very dark grey, also works at a more subtle level, according to at least one corporate image consultant. He's dealing in "subliminal message colors" that convey power. 

"The darker the colors are, the more credible you [seem]," says Patsy Cisernos, who heads up the consultancy firm Corporate Icon Inc. And while Cisneros says one has to earn Zuck's pedigree to get away with wearing sweats, she notes that entrepreneurs are a unique bunch in that they get to dictate their own company culture. 

The added benefit of Zuck's black hoodie and grey T-shirt is that they help to draw attention to his eyes, which in turn brings the focus back to his message. "It's all about getting those deeper tones up near the face," she adds, citing the effectiveness of blacks, greys, and French blues. Lighter colors, by contrast, "are a wash out," with browns and beiges taking away from your clout.  

Cisneros admits that Zuckerberg is something of an exception. For the rest of us, if and when you're pitching your business to investors -- or entering a more serious environment than you might be used to -- she suggests a compromise between Silicon Valley casual and Wall Street chic. For men, feel free to don those signature jeans, but couple it with an oxford button-down shirt and a jacket. "The jacket is key," she says, because it communicates your willingness to adapt to other business situations. Women should wear the same, and consider incorporating a color to match their skin tone and bring out the eyes. 

Ultimately, to create the most professional image, it's important to take cues from the existing business culture -- even when you're the one who created it.