what is colour blur?

The new version of DPP I downloaded corrects "colour blur" for all kinds of lenses... but I don't know what it is.

The other corrections are "peripheral illumination" (which gets rid of vignetting pretty well), "distortion" and "chromatic aberration" (which are both self explanatory).

I did a search before I posted this... my apologies if this has been discussed before...

Say "thanks" to google:
Click:" and color blur which occur by the physical characteristics of the lens or slightly remaining aberration. "

(Not a big "thanks" though, since it doesn't tell much specifics)

yeah, that's in the DPP help as well... I guess what I'm looking for is an example...