A rare Carte de Visite

This is slightly off -piste for this site but it's such a great find I wanted to share it: A 50p carte de visite from a local antique shop. I first noticed the slightly odd pose; it was only on closer inspection that I realised it's a double exposure and the chap is actually deep in conversation with himself.

This is relatively rare but by no means unheard of. Cartes de visite were cheap enough for people to have fun with them (many albums have matching back views on the page following a portrait for example).

If you look closely at the background you can see the join. These images were typically made using a sliding plate over the camera lens, covering half the image at a time. On this occasion the camera has moved ever so slightly so the two sides are misaligned. It's an easy enough effect to do: You just need a plate which slides to exactly the same point in front of the lens from either side. (note that it doesn't have to be the centre of the frame, as demonstrated by this picture).
Cokin filters used to sell a device for doing this (Cokin no. 346 Double Exposure Mask) and there are plenty on auction sites if you fancy trying it. Alternatively a bit of ingenuity with some cardboard should do the trick!