The output colour is marked on the lamp's frank. The date code HG suggests that the lamp was made in July 1976; probably at the company's Shaw factory.

Unusually, the lamp is designed to be operated on mercury control gear, and a snap starter is incorporated into the lamp's internal construction, in order to strike the arc.

As I have a working 400 Watt MBF lantern in the Collection, the Atlas Alpha 3, I decided to try this unusual lamp. The picture below shows it at full power - the apparent output colour is misleading; in reality, the colour temperature is similar to a "daylight" (approximately 6500K) lamp. This can perhaps be attributed to the age of this lamp, that the blue is not as vivid as it once was.

For a video of this lamp striking and then warming up to full power, please click the YouTube window below.