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Discussion Starter · #1 ·
With your projector showing 100% white, how uniform is the white intensity. There is always some fall off in the corners, but is it obvious with your projector?


Also, how smooth is the white in terms of color? Is there any noticable red or blue side, if so which side. What do you suppose might cause one side to be reddish and the other bluish?
 

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For my BenQ W5000 start up screen I have always used a 100% white window (not full screen) from my DVE disk. It fades in then is solid for a second or two. They don't serve much purpose other than checking the brightest point. There are better ways to check for edges or discoloration. A 100% white window (or less dependent on the projector) is the best way to check for hot spotting however. A 100% white window may be more appropriate for fp or rear projection CRT where contrast is of greater concern.
 

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My Planar 8150 has, near as I can tell (without measuring) perfect brightness and color uniformity across the screen. Pretty much every DLP I've had has been like that (thought my W5000 did have one corner that was a tad darker, probably from the manual iris I had all the way closed).


Liquid crystal technologies (LCD/LCoS) are know to have non-perfect uniformity though. Probably due to slight variations in the manufacturing process across the panel. Some RS1s would have bright corners with a black screen, and if you look around, you'll probably be able to find screenshots that show such issues.


Also as SteveMo mentions, if you've got a screen with gain, hot spotting is a possibility, where you'll have a bright spot on the screen, and it will move around as you do.
 

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The far left side of my RS1 projection is slightly but noticeably reddish; the right is too but less-so.


I chalked this up to chromatic abberation. Although I didn't notice it when I first got the PJ, so maybe it developed since then.


It's a non-issue when playing actual video. It is perhaps minorly irksome when I'm surfing the web with the white background.
 

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Epson 1080UB


Has some color uniformity issues. Left side is a little pinkish; right side a little blue. Both of my Sonys and my Epson have had this issue to one degree or another.


Intensity depends on a lot of factors such as room environment, calibration, settings, screen material, so that discussion might be meaningless.
 

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Benq W5000


100% white field---almost perfect except Right upper corner that is darker, I am almost sure that it is the lens and iris mechanic position that parasite the light path...


And yes like Stranger89 told us, DLP are probably the best technology right now for color uniformity.
 

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I found that my HD350 is much better in this respect than my previous AE3000, which was pink on the left and green on the right (only slightly, but visible on 100IRE even when properly calibrated). I haven't noticed dark corners with my HD350 either, though as I have a 2.35:1 screen and msotly tend to watch 2.35:1 content the corners are off the screen.
 

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Discussion Starter · #9 ·
So DLP projectors are usually uniformly white, while LCD types can have some color separation showing on the right or left side or both? And this is what I noticed, my DLP is perfectly uniformly white, with no colors differences at all. But the LCD I was looking at, definitely has reddish tint on the right and bluish-green on the left.


The center has some small area of whiteness near the center. This is very noticable at 100%, must less so at 80%.


How common is this for LCD projectors? Do most have this problem to some extent or are we talking only a few?


Here is a pic of the screen at 100%.
 

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Yeah, on a DLP even if the colorwheel segments are somewhat non-uniform, like an LCD panel, because they're spinning really fast, it will all average out across the screen (which is stationary relative).
 

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Quote:
Originally Posted by orion456 /forum/post/16958243


So DLP projectors are usually uniformly white, while LCD types can have some color separation showing on the right or left side or both? And this is what I noticed, my DLP is perfectly uniformly white, with no colors differences at all. But the LCD I was looking at, definitely has reddish tint on the right and bluish-green on the left.


The center has some small area of whiteness near the center. This is very noticable at 100%, must less so at 80%.


How common is this for LCD projectors? Do most have this problem to some extent or are we talking only a few?


Here is a pic of the screen at 100%.

I must be lucky because I haven't seen uniformity issues like that since my old Sharp 480p Projector from 1995. My Sony VW10HT from 2000 had very good uniformity up until I sold it a year ago and my current JVC RS1 doesn't show any of this and I am on my second bulb.


Ron
 

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Quote:
Originally Posted by orion456 /forum/post/16952206


With your projector showing 100% white, how uniform is the white intensity. There is always some fall off in the corners, but is it obvious with your projector?


Also, how smooth is the white in terms of color? Is there any noticable red or blue side, if so which side. What do you suppose might cause one side to be reddish and the other bluish?

Sort of a hard question to gather anything from without knowing throw distance, throw ratio, projector, screen, etc... Lots of factors will affect that.
 

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Discussion Starter · #13 ·

Quote:
Originally Posted by Jason Turk /forum/post/16967230


Sort of a hard question to gather anything from without knowing throw distance, throw ratio, projector, screen, etc... Lots of factors will affect that.

It's more a question of:


1. can you see the brightness falling off around the edges,


2. do you see a color difference from right to left,


for your setup and screen?


I wanted to get an impression of how many see some affect or no affect. On my Optoma H79, the white field appears very uniform in color and brightness. There is a slight fall off in the extreme corners.


I have since read that this is a problem with LCD machines, but I can't believe that people wouldn't complain about such a problem, so it must be somewhat rare.


I assume its some kind of alignment error where the lamp or the associated filters are at a slight wrong angle to the beam, and so don't separate the colors properly. If so, then only a factory fix is possible.
 

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Quote:
Originally Posted by orion456 /forum/post/16968559


It's more a question of:


1. can you see the brightness falling off around the edges,


2. do you see a color difference from right to left,


for your setup and screen?


I wanted to get an impression of how many see some affect or no affect. On my Optoma H79, the white field appears very uniform in color and brightness. There is a slight fall off in the extreme corners.


I have since read that this is a problem with LCD machines, but I can't believe that people wouldn't complain about such a problem, so it must be somewhat rare.


I assume its some kind of alignment error where the lamp or the associated filters are at a slight wrong angle to the beam, and so don't separate the colors properly. If so, then only a factory fix is possible.

No I did understand, my point is just that everyone should chime in with those details or it won't translate to much.
 

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Discussion Starter · #16 ·

Quote:
Originally Posted by wiatrak /forum/post/16968855


The problem is not rare, but you see the issue most on the 100% IRE on whole screen. And that is rare, when you just watch the movies...

Do you consider it par for the course, or a warranty repair kind of problem?
 

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Discussion Starter · #17 ·

Quote:
Originally Posted by Jason Turk /forum/post/16969290


No I did understand, my point is just that everyone should chime in with those details or it won't translate to much.

I assume if there are only a few responses, then most people don't have or don't consider the problem very serious for their projector.
 

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Quote:
Originally Posted by orion456 /forum/post/16969901


Do you consider it par for the course, or a warranty repair kind of problem?

As near as I can tell, some degree of nonuniformity is "par for the course" with liquid crystal tech. Whether it's a warranty issue or not is sort of a case by case thing. Sort of like convergence on 3-chip machines.

Quote:
Originally Posted by orion456 /forum/post/16969913


I assume if there are only a few responses, then most people don't have or don't consider the problem very serious for their projector.

You should go check the threads on any machines you're interested in rather than relying on everyone to know/think/care to drop into this thread and comment.


IMO if color/brightness uniformity are primary concerns to you, you're going to want to bias your search toward DLP, it's the only tech I'm aware of where they are really non-issues currently.


Somebody posted a picture of the Sim2 Lumis (DLP) next to an RS20 (LCoS) both showing a black screen and you could see the non-uniformity in the RS20, even though I think most here would say (legitimately) that the RS20 uniformity is not an issue.
 

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Discussion Starter · #19 ·

Quote:
Originally Posted by stanger89 /forum/post/16970984


Somebody posted a picture of the Sim2 Lumis (DLP) next to an RS20 (LCoS) both showing a black screen and you could see the non-uniformity in the RS20, even though I think most here would say (legitimately) that the RS20 uniformity is not an issue.

How would you calibrate a machine that has changing color temperatures across the field?


I'm really surprised I haven't read more about this when searching threads. It's hard to believe people just ignore an obvious non-uniformity and gush glowing reports of how LCDs beat DLP these days.
 

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Quote:
Originally Posted by orion456 /forum/post/16971297


How would you calibrate a machine that has changing color temperatures across the field?


I'm really surprised I haven't read more about this when searching threads. It's hard to believe people just ignore an obvious non-uniformity and gush glowing reports of how LCDs beat DLP these days.

The longer you follow this section of the forum, the more you'll recognize that image fidelity and display accuracy are not held very high in priority by a significant portion of manufacturers and forum members alike. Most consumers have little understanding of what a reference image is supposed to look like, and are happy with the what they see from most displays.


LCD projectors offer a relatively enjoyable image for the least cost. LCoS/SXRD projectors improve on LCD but also cost more. Some folks see rainbows with DLP displays and must settle for another technology. Others consider on/off contrast and black levels to trump various weaknesses of reflective LCD in their personal sense of image quality. I've compared the better DLPs to LCD/LCoS/SXRD projectors over many years as a consumer, a calibrator, system designer, and installer. I have access to sell all types, have owned LCD and DLP projectors, but personally prefer and professionally recommend DLP over the others, as long as rainbows aren't a problem for the client.


White field uniformity is not the only area of concern in evaluating a correct and/or enjoyable image. There is no perfect display for every system or viewer. Each consumer must determine what will suit their requirements and priorities. What's popular may not satisfy your needs or even produce the most technically superior image. Life should be more simple.....but it's not.


Best regards and beautiful pictures,

G. Alan Brown, President

CinemaQuest, Inc.

A Lion A/V Consultants Affiliate


"Advancing the art and science of electronic imaging"
 
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