Using photos as drawing references?

[aliberry]

Hi, new user here so excuse me if this has been covered - I did try a search!

I want to do some rough pencil drawings of 1940's film stars. I will be using photos released by the stars' agents (publicity photos), and other publicly-available photos as reference guides - but my illustrations won't look remotely like the photos. I hope to include my illustrations on a book cover - do I need to have copyright clearance from the photographers?
thanks!

[Sherif]

You state 'my illustrations won't look remotely like the photos' - so you could take the view 'who will know' (ahem! I'm not telling you to do that ).
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"Always be wary of any helpful item that weighs less than its operating manual."
Terry Pratchett

[CopyrightAid]

Copyright applies to a work regardless of the format that work takes and the act of making an adaptation of the work is itself a restricted act.

What you are producing is known as a derivative work so legally you should get permission form the photographer first.