Earliest Photographed Smile

Years ago I read somewhere that people only started smiling for the camera after film replaced photographic plates. The first practical film was developed by George Eastman in 1884. In early photography, sitters were required to pose for a long time in front of the camera and it was difficult to hold a smile for such a lengthy period: hence 'solemn' expressions were normal.

One of my minor obsessions (I have lots of these but they really are very minor) has been to try and unearth the earliest example of a smile caught on camera. This has proved to be rather difficult. I have examined many photographs from the early and mid 19th Century and there are plenty of 'enigmatic' expressions that may or may not be smiles. I just can't decide.

So far these are the two earliest I have found, but they are dubious cases. See what you think. The first dates from 1846 and is a photograph of 'The Porthole' at Edinburgh Castle. The photograph is attributed to David Octavius Hill and Robert Adamson. Is the soldier on the left smiling or not? I think he is and yet...

The next example is possibly even earlier but even more dubious. Taken by an unknown photographer sometime in the 1840s (the date is no more precise than this) it is a photo entitled 'Odalisque' and is French in origin. Is the model in the photo smiling? I really don't know.

Anyone who can solve this mystery for me -- the mystery of the first photographed smile ever -- will earn my gratitude, of course!