The “Break it Down” Blog

A lot of folks are confused when you talk about the Rainbow Effect or RBE for short. They don’t quite know what you mean. I ran across this perfect example of it, take a look:

It’s caused by single-chip devices trying to display Red/Green/Blue colors at the same time. Most rear project televisions use a color wheel to “paint” their colors onto the individual pixels. Most older wheels have the 3 primary colors on them while some newer wheels have 6 colors on them, primary and secondary color sets to help avoid such stark transitions and offer more shades of colors.

Rear projection televisions (RPTVs) also try and avoid RBE by using faster spinning color wheels, so the “painting” of the colors onto individual pixels is faster (and non-wheel based solutions like the Sony XBR or A2000 series of sets do not suffer from RBE because of how they are designed).

The easiest way to see RBE, or tell if you are susceptable to it, is to look at portions of the screen that offer stark contrast, like the example above. Light and dark borders that are moving quickly, then flick your eyes around the screen, quickly looking from the left of the screen to the right. The shift in your eye should allow you to see the change in colors along the borders of the highly contrasted areas.

Some folks don’t see RBE and can’t even when they try, so if you are one of those folks, just enjoy your TV. If you do see RBE very clearly, you might be a very “flicky” TV watcher, jumping your attention around the screen or there may be other causes of it. Either way, you have to decide if it’s annoying/distracting enough to avoid getting a wheel-based RPTV set. If it is, have a look at the JVC/Sony LCoS/SXRD solutions respectively, and I believe the new LED-based DLP from Samsung is suppose to dramatically reduce this as well.

NOTE: It is important to remind you that a lot of the newer RPTV sets coming out or have already come out this year are using ultra-fast (14k RPM) color wheels in addition to using more colors on their palletes and it’s rare that a lot of people can still see RBEs with them, so don’t get too discouraged. Go down to your local TV dealer and have a look. If you do decide to purchase a TV, get one with a 30-day no-restocking-fee return policy incase you get it home and then do see rainbows (which has happened to a few folks).