According to the https://plus.google.com/authorship page,
- Make sure that you have a profile photo with a recognisable headshot.
- Make sure that a byline containing your name appears on each page of your content (for example, "By Steven Levy").
- Make sure that your byline name matches the name on your Google+ profile.
- Verify that you have an email address (such as stevenlevy@wired.com) on the same domain as your content. (Don't have an email address on the same domain?
A brand is rarely an "author" - someone did the writing. Google wants that person tied to the work they created. Now, there may be ways "around" this but getting "around" stuff in SEO is why so many people scrambled so badly this year.
This page dissects it further: http://www.optimum7.com/internet-marketing/google-optimization/pros-and-cons-of-google-authorship-for-businesses.html
Most notably:
A company or brand’s Google+ page cannot be designated as the author of any web content. Therefore your company and brand name will not come up as the author in the web results.
**Warning:**If you’ve considered creating a company persona under the guise of a real person in order to have all authorship attributed to that particular Google+… Don’t do it! This really undermines AuthorRank and defeats the whole point of authorship. Google may also penalize you for trying to cheat their system… just as they’ve done for poor SEO practices through Google’s Panda-Penguin algorithm updates.
That's what I would follow. I would not suggest trying to game Authorship at all.