ANSI Lumens vs Color Light Output:
The Debate between LCD and DLP

Evan Powell, September 19, 2013

You may have noticed that several projector makers now publish a controversial new specification known as Color Light Output (CLO), along with the traditional ANSI Lumen ratings on their spec sheets.

Why do we need two different ways to measure a projector's brightness? In this article we'll explore how Color Light Output differs from ANSI lumens, and what it means to you as the projector buyer.


Does Color Light Output (CLO) matter?

Advocates of the new CLO spec argue that since three-chip projectors and single-chip projectors create white and color values differently, the ANSI lumen spec is not a valid way to compare their brightness. Certainly, if a 3LCD projector and a DLP projector both measure 3000 ANSI lumens (which is a measure of white brightness only), that means they can both project a white test pattern of equal brightness. But, they point out, who watches a white test pattern? Isn't it more important to know how bright projectors are when displaying full color images? And though the 3LCD and DLP both produce 3000 ANSI lumens of white, the color images on the DLP projector will often be dimmer than they are on the 3LCD. The CLO spec, it is argued, takes color brightness into account and gives buyers more info about the projectors they are evaluating.

"Not so fast, there bub," say those who object to the CLO spec. Though CLO measures color brightness, it does not take into account color accuracy. In order to get the highest ANSI lumen and CLO ratings out of a 3LCD projector, you must run all three chips wide open. And if the UHP lamp behind them has a green bias as they typically do, then the white light on the screen will have a green tint. So you may have a projector rated at 3000 ANSI lumens of white light and 3000 lumens of Color Light Output, but the picture looks bad anyway because the color balance is way off. Since the CLO spec does not address color balance, it gives buyers nothing new or important about the projectors they are evaluating.

Meanwhile, DLP engineers can compensate for green lamp bias with a larger red filter, so the white light from DLP is often a cleaner, more neutral white than you'd normally get from a 3LCD projector with all chips wide open. And if you try to calibrate out the green bias on the 3LCD its lumen output drops, sometimes a lot, and the ANSI lumen and CLO specs may no longer be relevant. So how does the introduction of a new brightness spec that is flawed in the same way the ANSI lumen spec is solve anyone's problem?

The thing is, people on both sides of the CLO debate have excellent points. But it is much easier to understand the controversy when you can actually see the differences in actual images rather than just talk about the concepts. So that's what we will show you in this article.


Definitions: ANSI Lumens vs Color Light Output

ANSI lumens: The ANSI lumen spec measures the brightest white that the projector can produce. It is measured by taking meter readings on a projected 100% white test pattern. The number you derive from the readings, say 3000 ANSI lumens, is the maximum brightness of white that the projector is capable of.

Color Light Output ("CLO"): The CLO method is similar, but instead of using a 100% white test pattern, one uses red, green and blue test patterns instead. Separate meter readings are taken for red, green, and blue, then added together. This time if we end up with 3000 lumens, that is the maximum brightness of color that the projector is capable of. So it is called color brightness, or color light output.

Why do different technologies create color differently?

All three-chip projectors, whether DLP, 3LCD, or LCoS, have three independent color channels for red, green, and blue. In order to produce white, all three color channels are turned fully on. So by definition, maximum color light output and maximum white light output are always the same. If a projector measures 3000 ANSI lumens, it will also produce 3000 lumens of Color Light Output.

However, on most single-chip DLP projectors made for business or classroom use, color is defined with a spinning color wheel that has not only red, green, and blue filters, but also a white filter and perhaps some secondary filters like cyan or yellow. The white filter allows white light from the lamp to bypass the color filters and boost the brilliance of the image. By doing this you end up with a very bright white as measured by the ANSI lumen method. But if you measure red, green, and blue independently and add them up like the CLO spec calls for, they don't add up to the total white value. So on a single-chip DLP projector with a white filter in the wheel, the CLO number would be less, often much less, than the ANSI lumen number. Since there is no marketing advantage to the makers of single-chip DLP projectors to quote CLO numbers, they never do.

The big question is...what difference does it make?


Contents: Introduction Executive Summary Test Set Up TEST 1: Uncalibrated
  TEST 2: Calibrated Concluding Thoughts

Reader Comments(14 comments)

Posted Sep 5, 2014 12:48:01 PM

By David

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One of the most comprehensive, well explained articles explaining (and showing) the differences in DLP and LCD color and brightness quality. Seeing the images side by side really helps...

Posted Jul 24, 2014 8:59:13 AM

By Home Theater Install

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AV_Integrated: I agree with your comment regarding RGB/RGB color wheel providing most accurate color display. I believe the Optoma HD30B is the model you need to compare to the W1070.

Posted Jul 16, 2014 8:34:52 AM

By AV_Integrated

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It would be excellent to have you guys run through this test again using three of the most popular 'cheap' home theater models. The Optoma HD25-LV (or similar) with a 2x, 6 segment (RGBCWG or RGBCYM) color wheel, the BenQ W1070 with the 6x RGB/RGB color wheel, and a Epson 2030 or 3020 model.

There's a lot of talk out there about the brightness specification of the Optoma models, but it seems that real world viewing won't actually allow it to deliver the same brightness, post calibration, or with normal use, that the W1070 is capable of delivering, and the cheaper Epson model may not be able to match either in regards to contrast, but may do very well elsewhere.

While dedicated home theater users may typically not care, for those with family room environments, non-dedicated spaces, or larger screens, the importance of getting post-calibration real world color brightness figures really seems like an important specification that can't be found anywhere else.

Similarly, it would be great for all reviews to include color wheel information and color wheel speed at differing input frequencies as most projectors don't have the same color wheel speed for 60hz content as they do for 24hz content.

Thanks for a very interesting read, even if I am getting to it a bit late!

Posted Jun 23, 2014 2:21:34 PM

By Bob

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This could happen but is extremely rare.

Posted Jun 23, 2014 2:20:23 PM

By Bob

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All the projectors you are considering have their merits. First consider your requirements - how much ambient light is in the room, what type of screen are you using, what size screen and what will you be watching?

For a dedicated home theater you don't really need 3000+ lumens unless you will be watching a lot of 3D content....most people don't after watching a few movies in 3D.

I do recommend moving up to 1080p, if within your budget. You may find that 3000+ lumens is too bright for a dedicated home theater. Also, look for a projector designed for home theater - for instance a color wheel with a white segment may focus on brightness instead of saturated colors.

Posted Jun 23, 2014 2:03:15 PM

By Bob

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Projection technology has been around for a long time now - both DLP and LCD projected images look great. I feel confident recommending both technologies without hesitation. If a customer is not happy with an image after adjustment, most projector manufacturers will assist customers or swap out the projectors.

The only companies really disputing this fact are the manufacturers of LCD panels and DLP chips. The DLP camp has not run a negative campaign for years, but this year at INFOCOMM, an LCD manufacturer had a side by side demo calling out the benefits of CLO. In the demo, both projectors were displaying images in high bright mode and both images were over-driven, and were not really acceptable, but the DLP image looked worse. When the settings were changed to a more user friendly mode, both projectors looked pretty good.

It seems that some projector manufacturers are determined to shift market share from one display panel technology to another. This might be a great idea in a growing market but the PJ market is relatively flat.

These component manufacturers should focus on finding ways to grow the PJ segment instead of shifting share.

At INFOCOMM there were several amazing LARGE screen displays that called out the benefits of projectors, including edge blending, LED, laser, interactivity, and digital signage. The industry needs to focus on the big picture and not components.

Posted Jun 11, 2014 10:36:19 AM

By Joshua

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Hey all, I just purchased a 730hd Epson with lCD and this is my first purchase of a projector. I'm wondering if I made a mistake for 2 reasons. First, it's 720p and does not do 3d. Second, will the LCD remain viable over time and product the best image? I'm considering swapping it out for Optoma DH1011 or a ViewSonic PJD7820HD.

Question is, will the DLP look as good as the 3 LCD from the Epson?

Posted Jun 4, 2014 11:25:00 PM

By Michael Miller

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And if you run the test after 3 years your DLP projector will have lovely sparkles all over it from the failed DMD chip.

Posted May 12, 2014 12:26:32 PM

By Lee

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Chris, I don't know where you are getting your information. First - no one knows exactly which LCD models have inorganic LCD chips, and many brands don't disclose this- so why you would you say that the #1 subject on the Projector Central forum is not relevant to a consumer anymore? Secondly, on what basis are you making the claim that DLP projectors use "lower quality parts"? Based on the Amazon top seller list today, the top four 1080p projectors are DLP, before a LCD projector is ranked. I have a hard time believing that they have "lower quality parts", when there are also sub $1k 1080p LCD projectors as well. I think the article shows that the image quality of a projector is not defined by a single spec, and this is where reviews by both this site and consumers really help consumer's decision making on a projector - regardless of the technology.

Posted May 5, 2014 9:40:36 AM

By chris

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Many LCD chips today are inorganic, so I don't know how relevant that is today, and I would also figure a true head-to-head test would be difficult as there are so many other factors, whether testing with brand new units, or older units with thousands of hours on them. For instance, it's been my opinion that most entry-level projector that use lesser DLP chips don't look as good (overall) as their LCD counter parts. Consider the Epson 5030UB and/or 6030UB and the Panasonic PT-AE8000U when compared to anything buy BenQ, Optoma, Vivitek, etc. for the same/ similar money. There are longevity issues, maintenance issues, and other set-up parameters to discuss as well, but in general... simply talking to the light output and it's perception in the image quality of the projector... I think LCD wins every time over DLP. When you start climbing the food chain a bit and start considering "better" LCOS units and DLP units, this changes some, but the bulk of the projectors purchased for home use are well under $5k and for those buyers it's hard to surpass the overall image quality of the LCD projectors offered in this pricing category.

Posted Feb 25, 2014 9:59:17 AM

By TimN

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It would be interesting to take this same evaluation and conduct it a year later or with say a 1000 hours on the projectors. Change the lamp and run the same tests again.

I'm guessing you would not get the same results on the LCD projector due to color decay from the organic compound in the LCD panels (chips). You could have a severely yellowish image from color decay and still meet the CLO ANSI lumen specifications.

This is the big advantage in my opinion for DLP projectors over LCD projectors. Same color from one year to the next regardless of how many times the lamp is changed.

Posted Oct 30, 2013 10:51:22 AM

By Darin

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Definitely some interesting results and comments. Thanks. I'm wondering if for Powerpoints in Test 1 you looked at anything like pie charts or line graphs that use multiple colors. Given the results in the Color Bar Test Pattern it might be interesting to see how Powerpoint presentations that are trying to differentiate information by color would tend to fare on each in a room with lots of room lighting on.

Posted Sep 19, 2013 2:04:23 PM

By Evan Powell (Editor)

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JVC's D-ILA and Sony's SXRD are both versions of LCoS. The projectors they make with this technology are three-chip units, so white light and color light values will always be the same on them. Sony quotes the CLO spec and JVC does not.

Posted Sep 19, 2013 1:23:38 PM

By Gary Hatch

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What would a Dila/LCoS (JVC/SONY) projector fall in this mix?

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