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drseid
09-13-2004, 11:44 AM
Hi All,

I just bought a new Samsung 5085W DLP HDTV (aka "The Kirk") a couple days ago. The set looked great in the store, and the picture also looks quite good after calibration at home...

Just one major problem... When the TV shows white lines or bright areas on dark/black backgrounds, I see these rainbows pop up out of the blue all over the screen. On some movies (Star Trek Insurrection in particular comes to mind as a major culprit) it is so bad that the picture seems unwatchable.

Anyone have any ideas as to how I can reduce the frequency of these rainbows popping up during movies with dark backgrounds?

Any help would be greatly appreciated... It really is too bad too, because HDTV football looked great on the set with almost no rainbows to be seen (except during a couple commercials).

Thanks,

---Dave

eqm
09-13-2004, 12:01 PM
Hi All,

I just bought a new Samsung 5085W DLP HDTV (aka "The Kirk") a couple days ago. The set looked great in the store, and the picture also looks quite good after calibration at home...

Just one major problem... When the TV shows white lines or bright areas on dark/black backgrounds, I see these rainbows pop up out of the blue all over the screen. On some movies (Star Trek Insurrection in particular comes to mind as a major culprit) it is so bad that the picture seems unwatchable.

Anyone have any ideas as to how I can reduce the frequency of these rainbows popping up during movies with dark backgrounds?

Any help would be greatly appreciated... It really is too bad too, because HDTV football looked great on the set with almost no rainbows to be seen (except during a couple commercials).

Thanks,

---Dave

Like the title said...this is by far and away the biggest drawback to a single-chip engine. If you really want to eliminate the rainbow, you'll need to move to a 3-chip model like some of the LCOS or LCD, or even move away from the micro-device category altogether and get more of a traditional RPTV. You can TRY pulling down some of the brightness/contrast/color controls (which are more likely than not jacked up for a showroom floor) by using Avia or Digital Video Essentials to properly calibrate. It will NEVER FULLY STOP the rainbow, but it may make it less apparent.

Hope this helps.

woodman
09-13-2004, 02:26 PM
Hi All,

I just bought a new Samsung 5085W DLP HDTV (aka "The Kirk") a couple days ago. The set looked great in the store, and the picture also looks quite good after calibration at home...

Just one major problem... When the TV shows white lines or bright areas on dark/black backgrounds, I see these rainbows pop up out of the blue all over the screen. On some movies (Star Trek Insurrection in particular comes to mind as a major culprit) it is so bad that the picture seems unwatchable.

Anyone have any ideas as to how I can reduce the frequency of these rainbows popping up during movies with dark backgrounds?

Any help would be greatly appreciated... It really is too bad too, because HDTV football looked great on the set with almost no rainbows to be seen (except during a couple commercials).

Thanks,

---Dave

Sorry Dave - but you've got a problem. Some people see the dreaded "rainbows" when others don't. If you're one of those unfortunate souls that see them and they bother you - you really have no alternative other than return the set and exchange it for a set using a different display technology. The only real "cure" for the problem involves the use of 3 DLP "micro-mirror chips" which eliminates the need for a spinning color wheel to separate the three color primaries (which is the culprit that creates the rainbows in the first place).

There are 3-chip DLP units in the marketplace, but as far as I know they are all front projectors - with pricetags that you don't want to know the extent of.

Don't mean to pee on your parade, but this is the simple truth of the matter ... sorry.

hershon
09-13-2004, 02:32 PM
I may in the future get an HDTV so I would appreciate your help in response to your previous posts. Are you saying that there is a good chance that most "affordable" HDTV's may have this so called "Rainbow Effect". If so, could that be detected by just turning one set on at say Best Buy or is it not that easy, and that this "rainbow" thing may appear sporadically without any regularity. What is the best way to avoid buying a set that may have this or is it just the luck of the draw? Thanks for any info



Sorry Dave - but you've got a problem. Some people see the dreaded "rainbows" when others don't. If you're one of those unfortunate souls that see them and they bother you - you really have no alternative other than return the set and exchange it for a set using a different display technology. The only real "cure" for the problem involves the use of 3 DLP "micro-mirror chips" which eliminates the need for a spinning color wheel to separate the three color primaries (which is the culprit that creates the rainbows in the first place).

There are 3-chip DLP units in the marketplace, but as far as I know they are all front projectors - with pricetags that you don't want to know the extent of.

Don't mean to pee on your parade, but this is the simple truth of the matter ... sorry.

woodman
09-13-2004, 03:07 PM
I may in the future get an HDTV so I would appreciate your help in response to your previous posts. Are you saying that there is a good chance that most "affordable" HDTV's may have this so called "Rainbow Effect". If so, could that be detected by just turning one set on at say Best Buy or is it not that easy, and that this "rainbow" thing may appear sporadically without any regularity. What is the best way to avoid buying a set that may have this or is it just the luck of the draw? Thanks for any info

The only sets that are vulnerable to exhibiting "rainbow" artifacts, are those that use the DLP (Digital Light Processing) technology that was developed by Texas Instruments. RPTVs that are CRT-based, and those that use LCD chips and/or LCoS chips - will not show any such problem.

So, if you're concerned about "rainbows", you can eliminate even the remote possibility of seeing them by avoiding any and all sets that use DLP chips.

topspeed
09-13-2004, 04:23 PM
Adding to Hershon's question for Woodman:

Do the new DLP2 chipsets and/or expanded color wheel eliminate the rainbow or bleeding artifacts? How do the LCoS sets compare to the LCD's inherent problems with blacks and smearing/ghosting on fast action sequences (a problem that immediately rules out LCD for me).

In other words, are there any thin, light, flat panel tvs that can hold a candle to the good 'ol crt rptv?

Thanks for your help Woodman.

cam
09-13-2004, 04:29 PM
Hey Woodman, I know that you have been in this field for over 60 years, and I sure appreciate all the free knowledge that you provide for all the members here. I certainly learn something everytime you post here. Just make sure you take care of yourself so you can be around for many more years to provide your wealth of knowledge about tv's. I'm going to possible need some of your advice in the near future. Cheers!

audiohead
09-13-2004, 04:33 PM
Sorry to hear about your problem. I have read in multiple threads on another forum that the more you watch a dlp device the less frequent you will see rainbows. Some people who saw them all the time hardly see them at all now. Good luck!

woodman
09-13-2004, 06:15 PM
... no, there simply isn't any display technology today that can compete head-to-head with the tried and true CRT-based RPTV. Not in any respect. Resolution? No contest. Black level? No contest. Accurate display of fast moving images? Again, no contest. Economical life expectancy? Once again, no contest.

The only things that these new display technologies have to offer is reduced cabinet size - which in the case of plasma means the long sought after "hang on the wall TV screen". This was a dream since the earliest days of television, and after about 40 years of research we now have it - but I'm not all that impressed ... especially with the pricetags that come along with 'em. The other "advantage" of the new displays is the elimination of the "convergence" problem - but I don't find this to be the quantum leap forward that some others think it is.

As for flat-out "bang for the buck", there's no denying that front projectors are out in front in that league. Of course, that means LCD, LCoS, or DLP based technologies - which involves some compromises in certain performance parameters.

topspeed
09-13-2004, 09:04 PM
Thanks Woodman.

EFE Speakers
09-13-2004, 09:25 PM
http://hometheater.about.com/library/weekly/aa101300a.htm

drseid
09-14-2004, 04:20 AM
Sorry to hear about your problem. I have read in multiple threads on another forum that the more you watch a dlp device the less frequent you will see rainbows. Some people who saw them all the time hardly see them at all now. Good luck!

Thanks Audiohead, and everyone else...

Well, it looks like I may have to hope that I too will see the rainbows less and less as I watch the DLP TV longer (as it has only been 2 and a half days, I could be seeing things at their worst right now).

One of the primary reasons I went with DLP is the lack of a screen burn-in problem that plagues CRT based rear projection sets. My parents had the problem on theirs, and when I too had it on mine (burning lines on each side of the widescreen from WebTv use), I swore off CRT based rear projectors... Too bad I seem to be one of the "lucky few" that sees these rainbows on DLP based sets... I guess I should have looked more closely at LCoS, LCD and similar technologies... I guess each one has its drawbacks.

---Dave

eqm
09-14-2004, 04:30 AM
RPTVs that are CRT-based, and those that use LCD chips and/or LCoS chips - will not show any such problem.

So, if you're concerned about "rainbows", you can eliminate even the remote possibility of seeing them by avoiding any and all sets that use DLP chips.

Sorry Woodman....the Philips LCOS is a single chip MDTV and certainly shows some rainbows. ;)

eqm
09-14-2004, 04:33 AM
Adding to Hershon's question for Woodman:

Do the new DLP2 chipsets and/or expanded color wheel eliminate the rainbow or bleeding artifacts? How do the LCoS sets compare to the LCD's inherent problems with blacks and smearing/ghosting on fast action sequences (a problem that immediately rules out LCD for me).

In other words, are there any thin, light, flat panel tvs that can hold a candle to the good 'ol crt rptv?

Thanks for your help Woodman.

The new 7-segment wheels (i.e. the new Mits units and the new Samsung units) seem to show rainbow even more to my eyes. I still went with a CRT RPTV myself about a year ago and haven't kicked myself in the slightest.

traut
09-14-2004, 08:17 AM
Well, it looks like I may have to hope that I too will see the rainbows less and less as I watch the DLP TV longer (as it has only been 2 and a half days, I could be seeing things at their worst right now).

... I guess I should have looked more closely at LCoS, LCD and similar technologies... I guess each one has its drawbacks.

---Dave
Dave,

Where did you buy your TV? If you've only had it for a couple of days, you could probably return it for something else. Most stores give at least a week.

drseid
09-14-2004, 08:18 AM
Dave,

Where did you buy your TV? If you've only had it for a couple of days, you could probably return it for something else. Most stores give at least a week.

I bought the set at Circuit City...

---Dave

traut
09-14-2004, 09:32 AM
I bought the set at Circuit City...

---Dave
I believe that CC has a 30 day no questions return policy. If you still don't like what you see after another week or two, you could always return the set.

IsmaVA
09-14-2004, 11:06 AM
Any system using one image forming device (hence a color wheel) will be suceptible to the so-called rainbow thing, be it DLP, LCoS, or LCD.

Higher frequency color wheels will definitively reduce the problem . .probably even eliminate it for some people.

What the orginal poster described sound like a diffraction problem by the microprism screen, more so since he never noted it at the store. I would return it and get a replacement just to rule that out. If the replacement still has the same problem then . . .oh, well . . .get a LCD, or a CRT based set.

drseid
09-17-2004, 11:17 AM
Thanks for everyone's help on this. I went back to Circuit City to look again at the Samsung DLP they had on display to see if I saw the rainbows on it, and this time sure enough I did. I also saw them on several other DLPs they had on display (showing the same material). My only guess is that the material that was showing on the day I bought did not cause the rainbows to appear...

So, the bottom line is I am trading in the Samsung DLP for a Sony LCD rear projector (KF50WE610). I definitely prefer the Samsung set's picture (sans rainbow), but I guess that is the cost of being in the "lucky few" that sees the rainbow effects on DLP. I watched the Sony very closely to make sure no rainbows could be seen on it, so I think I won't have a repeat. The one problem with the Sony is that I heard it has had a lot of QC issues with burnt out lamps and such... Hopefully they have gotten the problem under control as it has been about a year since its initial release... Wish me luck.

Thanks again everyone,

---Dave

hemifever
09-17-2004, 05:36 PM
I was really debating the Mitsubishi 52" DLP until I read this. I was leaning towards it over the Sony 60" XBR LCD due to the crisp picture. Sounds like I need to go back to the XBR. Do the Mit's DLP's have this rainbow issue as well? I would imagine they would.

cam
09-17-2004, 06:07 PM
This rainbow effect only affects certain people. Kind of like why some people are color blind and some are not. You should still consider the DLP, you maybe one of the lucky 90% that does not see the rainbow. But for the big pay per view fight, you may have a friend (or two) that sees this dreaded rainbow.

Mingus
09-18-2004, 07:54 AM
I am just wondering why some people see the rainbow effect and some don't. There must be a scientific expalanation. I never saw the rainbow effect, but I have met people who did while watching on the same screen.