Celebrities in historical news footage

I'm working in a documentary on the history of some pop culture aspects of the 20th Century. I've got some news footage of celebrities from the 1960's and '70's (ie: Liz Taylor walking out of a restaurant, Deborah Harry shopping). If I use this footage would this conflict with their right of publicity or is it ok to use celebrities in new-type footage, even though you're re-using it in a different context that it was originally shot for?

Any help in this matter would be appreciated!

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Regards,
Amy Lennie
The Rights Company
http://www.orbitci.com/rights.htm
mailto:alennie[_at_]interlog.com