Since human fire control began approximately 400,000 years ago, combustion has been an important source of light. The candle uses paraffin burning for incandescent light production. In 1879, incandescent bulbs appeared. The thermal excitation no longer came from an oxidation reaction, but rather from the Joule effect in a tungsten conductor. 1895 saw the birth of fluorescent sources, which were variations of discharge and X-ray tubes. The compact fluorescent lamp (centre) is the modern descendant. The laser was created on paper in the early 20th century and materialized in the 1960s. Its coherent, often monochromatic, narrow-beam, high-irradiance light has become essential in art and industry, and will remain a staple in science. Light emitting diodes (LEDs) have their origins in the 1960, firstly with low frequencies. Higher frequency LEDs have been added over the years.