A popular souvenir of the World’s Fair was the hold-to-light postcard. These postcards were unique because the image on them changed when held up to a bright light.
Hold-to-light postcards generally contained cut-outs on the top layer of the postcard overlaying another colored layer.
St. Louis’ Samuel Cupples Envelope Company produced a series of these postcards depicting many of the Fair’s buildings and attractions. When these colored photographs are held to the light, the Exposition building lit up.
The words ‘Official Souvenir Worlds Fair—St. Louis 1904’ appeared on the postcard.
Hold-to-light postcards remain a popular item with today’s postcard collectors
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