Smiling for Portraits

When did people start smiling for portraits and photographs? When you see images from the 1800s and early 1900s, how often are the subjects smiling? It seems pretty rare to me. Somewhere in the middle of the 1900s that changed. Now people expect a smile in a portrait.

Here is an interesting "morphing" of the US Presidents from George Washington to the present. Before Harry Truman, they all look pretty dour and statesman-like. But from Truman on, that begins to change. Truman through LBJ seem to have a wee bit of a smile going on. Nixon a bit more. Carter's wide grin looks downright goofy. Obama's head shot looks like that of a weatherman on the 10 O'Clock news.



I think I prefer the dour statesmen.

Update: Others noticed the same thing.