Candlepower

[Daniel Klistorner]

Hello,

It says in the Shipbuilder that Olympic and Titanic's lights were between 16 - 100 candlepower. Does anyone know how that translates to modern light bulb watts?

Daniel.

 

[Samuel Halpern]

Hi Daniel:
A standard 100 watt incandescent bulb produces about 150 candlepower. A 100 candlepower lamp would be close to a standard 70 watt incandescent bulb. Be careful though, the two concepts, wattage and candlepower, are very different things. Wattage is the power that goes into the bulb. Candlepower is a measure of luminous intensity of the bulb in a given direction. For example, a typical automobile highbeam headlight produces about 100,000 candlepower. Most the light in this case is reflected in a given direction.

 

[Bob Godfrey]

In 1912, domestic light bulbs were commonly 30 watt and rated at about 8 candlepower. I imagine the cabin lighting would have been of that order. Mounted in a light fitting with a shade/reflector to direct the light downwards, that would provide a beam of about 16 candlepower, at the bottom of the range quoted in The Shipbuilder. As Sam said, with a more focussed beam there can be a huge increase in candlepower. A pocket Maglite generates a 2000 candlepower beam from a couple of AA batteries, but remove the focussing head and reflector and you're left with a diffused light source which can hardly compete with a single real candle.
.

 

[Daniel Klistorner]

Thanks Bob & Samuel! Much appreciated!

Daniel.