Too Much Garlic wrote:
One word: flash.
Another word: what in the Elstree picture do you say constitutes as a repaint and not just flash washing out loads of detail?
Well, the neck is curved so direct flash just affects the front bottom section near the center a bit, but that's it. Also on Vader's right cheek, top right (outer) corner, and parts of the front faces of the mouth triangle, bottom, nose and Vader's right side. All you have to do is look for saturation in the look-up table of the grey scale values and that would indicate direct reflection off a surface due to flash. But obviously I don't look at areas like that to draw a conclusion about a repaint.
Here is just one small example. On the left the original paint on an area of the front of the neck, showing a clearly dark blemish against the gunmetal background. Second from left, the same area at the time of the Corbis photos, made darker. Third from left the same image made lighter. And on the right, the Elstree photo, again the same area. The dark blemish is gone in both the Corbis and the Elstree, but they are themselves different indicating different instances of touchup.