The flashbulb
1929 (Vacublitz, Germany)
Metal foil or wire sealed in a glass bulb with oxygen and fired by electricity: a bright, safe, smokeless flash, used once and thrown away.
How it began
Flash powder was dangerous, smoky and hard to time. In 1929 Johannes Ostermeier in Germany patented a bulb filled with aluminium foil and oxygen, sold as the Vacublitz; the Sashalite followed in the US.
How it works
A small battery current heats a filament coated with a primer, which ignites the metal inside. It burns in the oxygen in about 1/50 s, giving a bright flash, all within the sealed glass. A flash gun fires the bulb in step with the shutter.
Why it mattered
It was safe enough to use indoors among crowds, and it could be synchronised with the shutter. Press photographers with Speed Graphics and flashbulbs defined the look of news pictures from the 1930s to the 1950s.
Limits and what replaced it
Each bulb worked once, was hot after firing, and cost money. Electronic flash replaced it from the 1950s and 1960s, though cheap flashcubes lasted into the 1980s.
Today
Replaced by electronic flash; flashbulbs became a symbol of 1950s press photography.