While making the radio programme 'Rembrandt Today' (to be broadcast on Radio 4 11.30 a.m. 26th October) I came across the idea that most painted self-portraits don't accurately reflect left-right sides of the face because made using mirrors. What we usually see in a self-portrait by Rembrandt relates to what he saw in the mirror rather than how others would have seen him in this respect. In at least one case, the Kenwood House self-portrait with two circles, he corrected the left/right hand switch that painting from a mirror gave him - i.e. he put the palette in his left hand to avoid him looking like a lefthanded artist (something revealed by x-rays of the underpainting which showed him holding a brush in his left hand originally).
Now, self-portrait photography doesnt usually involve this left/right switch unless the printer accidentally flips the negative...not so likely in this digital age. Why would this matter at all, since nothing is added or taken away by a left/right switch. You might think it could have something to do with reading images of faces from left to right. John Walters, who makes non-reversing mirrors he calls True Mirrors, has another theory: he thinks that laterality matters in facial interpretation because of the hemisphere specialism of the brain. If a feature appears on the left side of someone's face we interpret it slightly differently from if it occurs on the right. Certainly if you look at a few portraits in mirrors the character of the sitter seems to change. If Walters is right, this suggests a further difference between photographic and most painted self-portraits: the photographic ones are truer to laterality, and this might result in a specific kind of realism beyond the usual ones trotted out when describing photographic realism - this one particular to facial reading...Just a thought.