This week's technique from Deke is about using Photoshop to fix a common problem that occurs in photographs, transverse chromatic aberration, otherwise known by its far less daunting name, color fringing. This phenomenon---caused by light breaking up into its primary components---leaves outlines of aberrant color around the edges in your photograph. Have no fear, however, because despite its daunting name, transverse CA is easily fixed in Photoshop. In this week's free movie from Deke's Techniques, Deke not only illustrates how the phenomenon occurs, but shows you how to fix it armed with the Lens Correction filter and a modicum of analytical ability.
http://www.deke.com/content/deke’s-techniques-014-fixing-chromatic-aberrations-photoshop