We've often talked of how many of the special effects in our films are invisible, that is most audiences won’t be aware they are looking at an FX shot. One such FX in All That Remains has been “face replacement”.
With such extensive use of archive footage, some of which contains the actual real life figures our actors are portraying, we didn't want to have the jarring effect of a character suddenly appearing quite different in one scene!
The most complex face replacement was a live action news reel footage showing the Emperor of Japan visiting Nagasaki, in one shot, we see the Emperor walking, surrounded by a crowd.
Using Adobe After Effects, we imported the archive shot and the footage of our actor. Using the masking tools we superimposed our actor’s face on to that of the Emperor and then using After Effect’s advanced and sophisticated tracking software we mapped it to the archive footage. The tracking tool did a great job, but because the original footage was so blurry, we had to do a fair bit of tweaking to the "face layer", frame by frame in some places, to make it match the movement more perfectly.
Here’s a great tutorial on the After Effects tracking tool…
Old footage tends to be very grainy, so we had to generate artificial grain (using the grain filter) on the actor’s face to help it blend it and then it was colour graded to match the archive footage. More colour grading work on the blended composition helped blend the two shots more seamlessly.
The most extensive use of face-replacement was, of course, old photos that are shown throughout the film.
We employed the same techniques to create more obvious effects too, such as keloid scarring or replacing eyes to create the effect of blindness causes by looking into the bright flash of the atom bomb.