Martha Katz-Hymen at the Jamestown-Yorktown Foundation wrote about this belief. It is true, but it isn’t the whole story.
It is true that people rarely smiled in old photographs because it is harder to hold a smile than a relaxed face, and photographs were not a quick “click” in the early years. But that is only one reason. The other is cultural.
“But an article by Nicholas Jeeves, recently published in the Public Domain Review, suggests that, when folks frowned, they did so for reasons as economic, social and historical as they were technological. Mark Twain thought as much. In one of his letters, collected by Jeeves, he wrote:
A photograph is a most important document, and there is nothing more damning to go down to posterity than a silly, foolish smile caught and fixed forever.
Twain wasn’t the only believer in the idiocy of the style. Look back at painted portraiture — the tradition photography inherited — and you’ll rarely see a grinning subject. This is, in fact, Jeeves’s subject. “By the 17th century in Europe,“ he writes, “it was a well-established fact that the only people who smiled broadly, in life and in art, were the poor, the lewd, the drunk, the innocent, and the entertainment.’
And read Nicholas Jeeves entire article, below. Jeeves is an artist, writer and lecturer at Cambridge School of Art. One excerpt: “A walk around any art gallery will reveal that the image of the open smile has, for a very long time, been deeply unfashionable.” http://publicdomainreview.org/2013/09/18/the-serious-and-the-smirk-the-smile-in-portraiture/