# DLP projectors and "Rainbow Effect" **URL:** \ **Category:** In My Humble Opinion\ **Created:** [June 14, 2012, 3:24pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146 "2012-06-14T15:24:53Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Mdcastle](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mdcastle](https://boards.straightdope.com/u/Mdcastle)\ **Post date:** [June 14, 2012, 3:24pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/1 "2012-06-14T15:24:53Z")
Around 2005-2006 I recall watching a DLP projector and found to to be virtually unwatchable because of the “rainbow effect” seen when moving my eyes or fast bright objects on the screen. Have DLP projectors gotten any better since then or is this still an issue? ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 14, 2012, 3:27pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/2 "2012-06-14T15:27:56Z")
Every projector I’ve seen using LEDs still has this effect. I believe it comes from firing the different colored LEDs that make up the white light not at the same time, a strategem that is not only easier to implement, but also saves power. You could get around it, I suppose, by firing off different grou;ps of different colored lights at the same time, but I don’t think anyone really has a serious problem with this effect, so it’s not going to get changed. ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [June 14, 2012, 3:44pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/3 "2012-06-14T15:44:25Z")
I’ve had DLP projectors as my primary TV for a dozen years now. I have seen ‘Rainbow Effect’ (RBE) on a few occasions, when I looked for it. Guests to my home have mentioned it only once. My conclusion is that while real, RBE is rare. I also think that your brain eventually compensates for the technology - just as with the flicker of cinema. Newer DLP technology has also started using faster color wheels and avoiding a bright, clear section. This has been done to minimize any possibility of RBE. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [June 14, 2012, 3:47pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/4 "2012-06-14T15:47:26Z")
I have a DLP rear projection TV. Never ran into this. It uses an incandescent bulb, not LEDs. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 14, 2012, 3:59pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/5 "2012-06-14T15:59:15Z")
No DLP projector uses LEDs, at least none worth mentioning. DLP projectors use a color wheel to sequentially change the color reflecting off of the single DLP chip. Better (and newer) projectors use faster color wheels that substantially reduce the Rainbow effect. We have a DLP projector with a [4x color wheel](http://www.projectorcentral.com/Optoma-H27.htm). I see the rainbow every now and then, but nobody else has ever complained (I’m probably the only one who knows what to look for). ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [June 14, 2012, 4:01pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/6 "2012-06-14T16:01:26Z")
> [@beowulff](#): > > No DLP projector uses LEDs, at least none worth mentioning. > DLP projectors use a color wheel to sequentially change the color reflecting off of the single DLP chip. Better (and newer) projectors use faster color wheels that substantially reduce the Rainbow effect. We have a DLP projector with a [4x color wheel](http://www.projectorcentral.com/Optoma-H27.htm). I see the rainbow every now and then, but nobody else has ever complained (I’m probably the only one who knows what to look for). My apologies. I thought by “DLP” he meant a {Light Emitting) Diode Light Projector, in which I see this color separation all the time. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 14, 2012, 4:01pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/7 "2012-06-14T16:01:55Z")
> [@TriPolar](#): > > I have a DLP rear projection TV. Never ran into this. It uses an incandescent bulb, not LEDs. I doubt it’s incandescent - probably it’s [HID](http://en.wikipedia.org/wiki/High-intensity_discharge_lamp). ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [June 14, 2012, 4:32pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/8 "2012-06-14T16:32:23Z")
> [@beowulff](#): > > I doubt it’s incandescent - probably it’s [HID](http://en.wikipedia.org/wiki/High-intensity_discharge_lamp). I only used that term in contrast to LEDs. It may be one on those. Inside the ‘bulb’ is a small glass cylinder. I can only look at it from the front (end on to the cylinder) so I can’t tell what’s inside, but it probably is an HID. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [June 14, 2012, 5:35pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/9 "2012-06-14T17:35:09Z")
> [@jasg](#): > > My conclusion is that while real, RBE is rare. I also think that your brain eventually compensates for the technology The first couple of days my brother bought his DLP (about 5 years ago), I couldn’t watch the TV for more than a couple minutes at a time. I saw the rainbow effect with every slight change of my gaze, and it gave me a headache. However, a few days in I got used to it, and no longer see the rainbows, unless I consciously look for them. And even then they are nowhere near the intensity of when I first started watching on a DLP set. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [June 15, 2012, 3:20pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/10 "2012-06-15T15:20:45Z")
I think projectors that use 3 DLP chips won’t have the rainbow effect. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 15, 2012, 5:02pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/11 "2012-06-15T17:02:21Z")
> [@AaronX](#): > > I think projectors that use 3 DLP chips won’t have the rainbow effect. True, but those projectors are fantastically expensive. ---
**Author:** ![Valgard](https://avatars.discourse-cdn.com/v4/letter/v/7feea3/32.png) [@Valgard](https://boards.straightdope.com/u/Valgard)\ **Post date:** [June 15, 2012, 5:57pm UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/12 "2012-06-15T17:57:22Z")
I have a Samsung DLP set; it’s relatively old (over 5 years) and I can see the rainbow effect (rapidly change my focus from one side of the screen to the other). I’m told that not everyone can see it. Oddly enough, although my vision isn’t great (I wear glasses) I could see plenty of “jaggies” on diagonal lines at the first all-digital movie I saw whereas none of my friends noticed anything at all. ---
**Author:** ![Mdcastle](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mdcastle](https://boards.straightdope.com/u/Mdcastle)\ **Post date:** [June 16, 2012, 2:20am UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/13 "2012-06-16T02:20:09Z")
As a side note, after my old projector was in the shop they broke it further. Originally the screen was crooked which they couldn’t fix because the optical assembly was bad but now there’s also pink band on top. My sister didn’t mind the crooked screen but I considered it unnacceptable which is why I brought it into the first place. It’s not like they could do anything, but do I have grounds to complain anyway. I did mistakenly say “yes” when the guy dropping it off asked if the pink banding was the problem, I thought he meant the convergence was 1 pixel off which is they way it might have been, not that there was a 200 pixel or so wide band at the top ---
**Author:** ![Ponch8](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ponch8/32/9883_2.png) [@Ponch8](https://boards.straightdope.com/u/Ponch8)\ **Post date:** [June 16, 2012, 3:08am UTC](https://boards.straightdope.com/t/dlp-projectors-and-rainbow-effect/625146/14 "2012-06-16T03:08:42Z")
I notice it more with the really crappy projector in one of the meeting rooms at work than with the nicer projectors in other rooms.