How to Use Color Correction Filters for Canon Speedlites

The Canon Speedlite 600EX-RT (price & specs)

Good article by Eric Stoner on Canon Digital Learning Center about how to deal with colour correction when using a Canon Speedlite flash.

One key element in flash photography is learning how to manage mixed or unbalanced lighting. In other words, correcting the balance between the color temperature of the light emitting from the Speedlite and with the background.