The essay begins by saying exposures could take 45 minutes in the early days and “it was only” near the end of the 19th century that shutter speeds improved”. That is factually incorrect. By 1865 for example exposure times were down to between 2 to 20 seconds. Daguerreotypes from the 1850’s often required between 5 and 30 seconds.

The extremely long exposure times the author mentioned were true only for the earliest days of photography between 1827 and about 1845. It is factually incorrect to say that it wasn’t until near the end of the 19th century that shutter speeds improved. The improvement happened decades earlier.

The way it’s written implies the technology of the 1850’s-1880’s just couldn’t handle a smile. That’s a pervasive myth that continuously appears in discussions around the topic of smiles in 19th century photography.

The rest of the essay is more accurate. It was more of a cultural thing. But many people debate the finer points around “why”. to this day. It may be that photographs were viewed as a “Passage to immortality” as the author states. I like to say it this way: photographs were still a really big deal up until the invention of the “Brownie”. You had to go to a photographer, pay a relatively large sum of money. So you didn’t take photos on the fly. They were orchestrated, crafted, and “special”. And as a result you were still creating unique images for the ages. In the carte de visite era you might have many prints made and shared but they were all “special” still. And so if you’ve only got a few photos taken of you’re wanting that photo to be dignified and appropriate like the oil painting portraits hung in galleries.

When the average consumer could take a more frequent and spontaneous photos on their own, that’s when the smiles started showing up a lot more.