This Benjamin Model B lightmeter dates from around the 1940s and was intended for measuring the brightness of room lighting – particularly in workplaces. It was sold by the Benjamin Electric Co, of Tottenham, who specialised in workplace lighting, but made by Weston Electrical of Surrey, England.

This particular example was used by Percy Skipworth and his son Reg Skipworth, owners of the small electrical contractor S Charlesworth & Co in Oldham, Greater Manchester, much of whose business was for textile mills.

Such meters were promoted with the idea that the correct level of lighting would boost worker productively. It is activated by light falling onto the circular sensor, generating a current that causes the needle on the dial to move. On the back is a table of lighting levels thought suitable for different sorts of workplace.

This case for a Benjamin Model B lightmeter dates from around the 1940s. It was sold by the Benjamin Electric Co, of Tottenham.

This baffle, also known as a mulitplyer, fitted over the light sensor of a Benjamin Model B lightmeter to reduce its sensitivity for measuring higher lighting levels.

This baffle, also known as a mulitplyer, fitted over the light sensor of a Benjamin Model B lightmeter to reduce its sensitivity for measuring higher lighting levels.

This box stored a Benjamin Model B lightmeter.