Sorry for the rather convoluted title. I'll try to explain with an example. I was watching the new DVD of Citizen Kane (phenomenal restoration job, BTW) and I realised that when they made Orson Welles (playing Kane) look old, he looked nothing like he did when he really did grow old. This made me realise that I've never seen an actor in an older movie who has been made to look old who actually looked that way when they became old in real life. Can anyone think of an exception to this rule?