Part 3/8:
The principles behind flash photography are rooted in the need to generate intense bursts of light. Early solutions included elaborate systems that produced an equivalent brightness to the sun. This challenge was effectively tackled by electronic flash units that employed flash tubes filled with xenon gas.
When charged, these tubes can generate a bright flash produced by a high-voltage discharge through the gas. These inventions, however, remained on the periphery of consumer use until the mid-20th century due to their cost.