Commercial photographers began producing this spectacular phenomenon for fun and profit and—as I have found while researching early portrait photography—thereby helped feed media fascination ...

In the mid-19th century, photographs with ghostlike figures became collectible amusements thanks to the invention of the stereoscope – a device that created three-dimensional optical illusions.

These are just a few of the 100,000 portraits Sami Aziz captured in a single year along Philadephia's iconic South Street.

Commercial photographers began producing this spectacular phenomenon for fun and profit and – as I have found while researching early portrait photography – thereby helped feed media ...