Editorials

METAL HALIDE LAMPS FLICKERING

Traditionally, metal halide lamps have not been favoured by lighting designers. One of the reasons is that people perceive them as flickering. This has to do with the frequency that typical lamps operate at (50hz)

As metal halide is usually specified in commercial situations, flicker is not usually an issue. If however it is used for instance in an office environment, where the lamp is close to the working surface (less than 3m), and possibly with white walls, then there is a good likelihood that flickering will be noticeable.

With traditional technology – magnetic gear and quartz lamps - the usual methods to minimize flicker are:

Use in commercial areas only, or where flicker won't be an issue

Use good quality branded ballast and lamp

Keep fittings above about 3m from the floor

 

Note that most quartz lamps require a burn in period of about 100 hours. As most lamp suppliers will point out, the burn in period usually solves the flickering problem as well as colour issues

 

Over the last few years there have been improvements in the technology of both lamps and control gear

Ceramic lamps: this is a different technology to quartz, and has little to no flicker. These lamps can be used with both magnetic and electronic control gear (although with electronic, it is very important to check the compatibility of lamp and gear)

Electronic ballasts: one of the numerous advantages of using electronic is the elimination of flicker altogether
These technologies have provided the lighting designer with more options especially in retail lighting.