THE RAINBOW EFFECT
The rainbow effect is only present in single chip projectors. In these projectors the light goes through a spinning RGB colour wheel, to the DMD and then projected. As such, a projector displays colors sequentially to build an image, meaning they show the entirety of one colour before moving to the next. The wheel spins too quickly for us to be able to see these colors individually, but can create two annoying byproducts. Firstly, the colour wheel when spinning tends to make a buzzing noise some find annoying, but others can block out. Secondly, the rainbow effect.
The rainbow effect, although sounding quite innocent, can become a huge burden on image quality. The effect is essentially when you see flashes of red, green and blue over an image. However, not everybody is susceptible to it. If you’re part of a group that can’t see it, don’t go looking for it.
Summary
The rainbow effect flashes red, green and blue across the projection. It is only common in old single chip DLP projectors.
SOLUTIONS
Unfortunately there aren’t too many solutions for this other than purchasing a new projector. Often the rainbow effect is only seen when the colour wheel spins too slowly. Of course this is more apparent in older and cheaper projectors. Further to this, the effect only becomes significantly evident when prominent white objects are against black backgrounds.
This by no means should discourage you from buying a DLP projector, perhaps just ensure you can either test it out first or lean in the direction of a 3 chip DLP projector. If you’re worried about your susceptibility to the rainbow effect, think about investing in either an LED or LCD projector instead.
