Paul C. Buff, Inc. Technical Forum

Paper:
Brand: Savage
Color: Artic White
Camera: D300
Lens: 28-70mm f/2.8
Background lights: White Lightning x1600 with 7" reflector, flagged with wood bifold panels
Mainlight: Alien Bee b800 through a 4ft octobox
On the floor was a generic white tileboard.
I color corrected using a Photovision white, grey, black fold out thing.

So those are all the details, why is there blue around her head?!?!?!

Nevermind, I found the answer....

looks like CA, or chromatic abberations. This frequently happens in a high contrast situation, dark subject on a light background. Different wave lentghs of light (different colors of light, all of which are contained in white light) bend through matter at different rates. At this sharply contrasting edge, the blue is straying from the rest of the colors a little, and appears as a blue halo. Other colors can appear, too. (purple or magenta are most common, though I would suspect different WB settings can change one color to another). This is an optical function of a lens, and not necessarily an indicator of a bad lens, as all optics are prone to some type of abberation.

A better explaination:http://en.wikipedia.org/wiki/Chromatic_aberration