Artifacts with PD100
 

We have just shot a workshop in a school - all the uniforms are red so there are very bad red blocky artifacts. Has anyone any experience with how to aviod this using the PD100? Shot on manual between f2 and f5.6 - set white balance using white card, all other colours are ok.

And - has anyone any suggestions for what we could do in editing to minimise them - though I do know rubbish in rubish out.

I use Final Cut Pro HD - I have tried anti-aliasing which does minimise it a bit but of course blurs the whole image.

I dont know of any plug ins and i'd be happy to hear any suggestions.
Thanks, Alice

There is an image of the artifacts here
http://www.flickr.com/photos/37002602@N00/684825686/