same-color logo & background sometimes don't appear the same

I’m using the Twenty Ten theme. I created a logo with a background color of #070f41. I also specified the background color within the content area of the site as the same #070f41 in style.css – #wrapper { background: #070f41;

On my calibrated monitor I see no difference in those colors, which is of course as it should be. However, my business partner, using a new Mac Air, sees the dark blue of the logo and the rest of the site as different enough to be distracting; he sees a border on the right and left of the logo. We both have “picky” artistic tendencies 🙂

Have you ever heard of this? Here’s a screen shot that looks perfect to me, but for which he sees the different colors. I’m linking to this screen shot instead of the site because the site now has a border around the logo to disguise the difference on the Mac Air. Does anyone see the colors as different, and if so on what system.

http://dl.dropbox.com/u/16620406/dark_bg.jpg