Unicam SP 500 spectrophometer, c 1949.
© Science Museum / Science & Society Picture Library
The Unicam SP 500 was developed as a rival to the Beckman DU spectrophotometer. They were both point by point spectrometers and could not record a continuous spectrum. A spectrophotometer is an instrument for measuring the intensity of light in various parts of the spectrum, especially as transmitted or emitted by a substance or solution at a particular wavelength.