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Color science

Could Quantum Dots improve night viewing?

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Could Quantum Dots improve night viewing?

Ray Soneira, the display expert behind DisplayMate, just posted a great, in-depth piece that looks at Apple's new Night Shift feature.

While Night Shift does work as advertised, Ray suggests that Quantum Dots may offer a better alternative for night viewing. Using data from the Quantum Dot-equipped Vizio R65, Ray shows that Quantum Dot displays can be tuned to reduce the amount of blue energy in the troublesome 460-480nm range just as much as Night Shift, while still delivering fantastic picture quality...

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Color and Visceral App Design

Visceral refers to the gut, rather than the mind. Our brain may try to talk us out of jumping off a cliff, but as soon as we take that first step into the void, our guts take over. We respond with a rush of emotion and we can’t help but scream from terror or euphoria. It’s a purely visceral reaction. [...]

So here’s my theory: I believe that introducing visceral elements into an app will take it past the point of just being awesome. It will make your app speak to the subconscious, built-in affinity that humans have for the physical properties I mentioned before.

That's Rob Foster, co-founder of Mysterious Trousers, defining his theory about the importance of visceral elements in application design. The whole piece is well worth reading, especially if you are interested in design or have ever wondered just why Angry Birds is so unbelievably addictive.

In the quote above Rob is talking about the power of little kinetic events in applications like the bounce you get when scrolling to the bottom of a page on the iPhone or the satisfying little "pop" noise you hear when creating a new task in Clear. His point is well made, getting the details of these visceral elements right can clearly take an app from just useful to a truly engaging and even addictive experience for users.

While Rob's piece focused on the impact of animation and sound, I wondered how color might factor into visceral application design.

Color choice is not just about beautiful graphics- it can also have a powerful physiological effect on us. We have a measurable response to aggressive colors like red, which may even cause a spike in testosterone levels. In fact, recent studies suggest that that the color of a uniform can affect the outcome of an Olympic wrestling match and onscreen colors can even influence how much you pay for something on eBay.

As mobile display technology improves, with more lifelike color and wider dynamic range, application designers may find that color becomes an even more powerful tool to elicit visceral responses from users.

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Are tablets up to the task of accurate color testing?

Finally getting around to posting a follow-up to a follow-up to John The Math Guy’s recent series on color gamut size, colorblindness and tablet displays. I thought I might be able to at least shed a little more light on his question about the differences in color accuracy between some of these devices. In his testing, John found no statistically significant difference in scores among different people taking the EnChroma colorblindness test on different devices. I found this somewhat surprising since, in my experience, even tablets with similar color gamuts tend to show colors with very different levels of accuracy.

iPad mini color gamut and Gretag Macbeth colors against sRGB in CIE1976

To show what I mean by that, I measured how two different tablets show the colors found in the Gretag Macbeth color checker chart.Nexus 7 color gamut and Gretag Macbeth colors against sRGB in CIE1976

As you can see, the iPad mini and Nexus 7 each produce very different colors, even for those colors that are actually inside their gamuts.

For example, even though the iPad mini has enough gamut coverage to accurately display the Gretag chart’s deepest blue, it cannot do so without distorting the image in another way. This is because of data in the underlying image standard- most content today is encoded in the sRGB standard. If the iPad were to show that Gretag blue correctly, it would not have enough color saturation headroom left over to show you a different color if a deeper blue, say right at the bottom of the sRGB triangle, were called for.

A good real world example of this can be found in the picture below of my bloodhound, Louisa, racing down the beach at Carmel, CA. The middle of the sky in this image is right on the edge of the iPad’s color gamut, very similar to the Gretag blue in the charts above, while the deepest blues found in the ocean fall outside the iPad’s gamut.

Out of gamut colors at beach

If the iPad were striving for accuracy at all costs, it might map both colors right on top of each other at the edge of the gamut. There’d be no visible difference between the two in this case and the quality of the image would suffer but at least the sky would be accurate. In order to avoid this scenario, the designers of these devices have decided to compromise on accuracy so they can show a full range of color differences to the user.

They do this by remapping colors inward, away from the edges of the gamut, effectively compressing the gamut even further so that otherwise out-of-gamut colors can be seen. This is a good solution given the gamut limitations of the device since it results in more pleasing, if less accurate images.

As newer devices trend towards wider color gamuts this kind of compromise should become a thing of the past. In fact, tablet designers may be working on the reverse issue- how to avoid oversaturating images that were encoded for smaller gamuts.

Great, how does this relate to colorblindness again?

iPad mini vs Nexus 7 color accuracy comparison in CIE 1976

Taking another look at the Gretag results from the two devices plotted on top of each other, there clearly are major differences. But, in the reds and greens, two colors associated with a common form of color blindness, the devices are relatively close. So, the simple answer may just be that colorblindness tests do not require pinpoint accuracy to be effective, at least as basic screening tools.

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Color of the year for 2013 falls outside sRGB gamut

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Color of the year for 2013 falls outside sRGB gamut

Pantone recently announced their color of the year for 2013, a deep shade of emerald green that they call “Emerald 17-5641.” It’s a great color but there’s a catch- most displays cannot accurately show it.

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So you bought a 4K TV, now where is the 4K content?

Content is king. One of the biggest challenges for emerging display technology is content availability. Whether it’s 3D, 4K or wide color gamut, these new features simply aren’t worth much without access lots of great, optimized content. As new 4K TV’s begin hitting store shelves this year, they are entering a content vacuum.

Standards bodies like the Consumer Electronics Association (CEA) and International Telecommunication Union (ITU) are still working out the precise definition of marketing terms like Ultra High Definition TV (UHDTV). Proposed standards could include support for eight million pixel resolution, extremely wide color gamut and 3D content. But, today, there is almost no content out there that takes full advantage of all of the exciting capabilities of the new sets.

And, unlike the transition to HDTV, there’s no government-mandated switch on the horizon to force broadcasters to get on board.

CIE 1931 rec.2020 vs rec.709

At least one set-maker is taking it upon themselves to solve this problem by delivering both the 4K content and hardware. Sony announced last week that it will loan a 4K Ultra HD video player loaded with UHD content to buyers of their new 84” UHD television. The selection of 4K content on this player is fairly limited for now, but as more titles are released, this approach could help drive adoption of high resolution and wide color gamut formats.  I wouldn’t be surprised if other set makers started following suit, though Sony does have an inherent advantage, owning a movie studio.

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How does ink thickness change the appearance of printed color?

We typically focus on color as it relates to displays here at dot-color, but I came across a fascinating post about color in the print industry from John the Math Guy that I had to share. In this post, John takes a close look at how ink looks at different thicknesses and uncovers the reasons for some seemingly unconventional color-naming habits in the print industry.

What happens when we double the amount of ink on the paper? …it would seem that the thick layer of magenta is a lot closer to red. The plot below shows the actual spectra of two magenta patches, one at a larger ink film thickness than the other. The plot leads one to the same impression – that a thick layer of magenta is closer to red in hue than a thin layer.

Read the whole thing here:  http://johnthemathguy.blogspot.com/2012/09/why-does-my-cyan-have-blues.html

 

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Updated: How does the iPhone 5’s color saturation measure up against Apple’s claims?

Commenter William thankfully double checked our math and we've corrected a small error in our % NTSC calculation.

We finally got our hands on an iPhone 5 yesterday. I tried asking Siri if she really has 44% more color saturation but she wouldn’t give up the goods, so I went with plan B and aimed our PR-655 spectroradiometer at the phone to find out just how impressive the screen really is. A lot has already been written about this display, but not much empirical evidence has been published about the color performance. How does the screen actually stack up to the marketing claims?

In short, Apple did an exceptional job improving color saturation and display quality in general, but the unit we measured just missed the 44% more color saturation claim.

Measuring Up

The 44% more color claim for the iPhone 5 is the same claim Apple made for the new iPad. As with the iPad, increasing the color performance of the iPhone 4S by 44% of NTSC 1953 gamut, measured using the CIE 1931 color space, would result in color saturation matching the sRGB color standard.  Using these standards as the goal posts, we measured the iPhone 5 at 70% of NTSC 1953 in CIE 1931, a 39% increase from the iPhone 4S, which measured at 50%. That’s 5% less of an improvement than Apple’s 44% claim and just 99% of sRGB (measured against the sRGB primaries).

While 5% less might seem like a big deal, getting to 99% of sRGB is a major feat and will result in tremendously noticeable color improvement in the phone. Additionally, color filters are notoriously difficult to manufacture. Slight variances in performance like this are common and most likely outside the range of a just noticeable difference for the average person.

If you want to know more about NTSC, CIE and sRGB, and why we are using standards from the 1930s, I have written extensively about this issue in the past.

How did they do it?

Much like they did with the new iPad, Apple significantly improved the color filter performance of the iPhone 5. Based on our experience, this type of improvement typically means that the display requires 20-30% more power to operate at the same brightness. Considering that the display is already a major source battery drain on the phone, this further underscores the engineering effort Apple made to keep battery life about the same as the 4S.

Let’s take a quick look at the changes in each of the red, green and blue color filters, starting with white, which is all three filters turned on:

Looking at the white spectrum of the iPhone 5, we see that the new color filters are very similar to those of the new iPad. Compared to the 4S, the peaks are slightly narrower, which improves color purity. In order to meet sRGB, they also moved to deeper reds and blues.

As with the new iPad, the biggest difference between the 4S and the 5 is in blue. Apple moved the peak to a deeper blue but, more importantly, they narrowed the filter so less green light leaks through. The green leakage causes blue to look a bit “aqua” on the 4S.

Retinal neuroscientist Bryan Jones looked at both displays under his stereo microscope earlier this week. His close-up shots really show off the difference in blue filters.

Apple again chose a slightly deeper wavelength of green which is less yellow and eliminated some of the blue leakage that had been muddying the green on the 4S.

The change here is subtle but as with the other filters, the peak is narrower, deeper in the red and leakage is reduced. One difference worth noting is that, while we are seeing less peak leakage in the red filter, there had been relatively broadband leakage across yellow, green and into blue that has been largely eliminated.

Conclusion

In all, it's an exceptionally well-calibrated and accurate display for any kind of device, especially a smartphone. Apple has gone to great lengths to design a screen that brings the vibrancy of sRGB to the palm of your hand. If you are not familiar with color filters or the inner-workings of LCDs in general this great live teardown by Bill Hammack is well worth watching: http://youtu.be/jiejNAUwcQ8

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Seeing red: can color change your spending habits?

Color can have a powerful physiological effect on us. This should come as no surprise to anyone who’s ever been wowed by a Monet or a Rothko. But color can affect us in ways you never imagined. Recent studies suggest that that the color of a uniform can affect the outcome of an Olympic wrestling match and onscreen colors can influence how much you pay for something on eBay. In one study, researchers found that Olympic wrestlers wearing red won as much as 60% of the time, even against evenly matched opponents (who wore a different color).

Similarly, in a Journal of Consumer Research study on the impact of color on consumers who buy items on auction sites like eBay, authors Rajesh Bagchi and Amar Cheema found that "red background color induces aggression through a feeling of arousal and it increases aggression relative to blue or gray backgrounds. This causes individuals to make higher bids in auctions but lower offers in negotiations.”

Why? The exact mechanism remains a mystery but researchers see some evidence that aggressive colors like red may actually cause a spike in testosterone levels.

I find it particularly fascinating that color choice did not specifically correlate to the price someone paid for an item. Instead, the colors drove more or less aggressive behavior, which lead participants to either seek the best deal possible against a salesperson or to beat out competing bids in an auction.

It got me wondering how retailers might be using color to influence purchasing. A quick survey of some popular online shopping destinations yielded potentially interesting results. Since product background is not always in the control of the retailer, I looked at the “add to cart” areas of three popular online retailers: Apple, Amazon and eBay.

All three employ a lot of blue, a calming color, in their ‘add to cart’ areas. Apple uses a shade of green, another calming color, for the “add to cart” button. Amazon lists the price in a dark red, while Apple uses a lighter shade to accentuate free shipping.

Next time you find yourself shopping either online or brick and mortar, take note of the colors around you - you may be surprised by how far your environment is being manipulated to get you to pay more.

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Color Space Confusion

For many who are new to the world of display measurement, the prevalence of two distinct, but often-interchanged color spaces can be a source of confusion. Since my recent post about the color performance of Apple’s new iPad, a number of people have asked about this topic, so I thought it would be worth a closer look. In the world of displays and color images, there exists a variety of separate standards for mapping color, CIE 1931 and CIE 1976 being the most popular among them. Despite its age, CIE 1931, named for the year of its adoption, remains a well-worn and familiar shorthand throughout the display industry. As a marketer of high color gamut display components, I can tell you from firsthand experience that CIE 1931 is the primary language of our customers. When a customer tells me that their current display “can do 72% of NTSC,” they implicitly mean 72% of NTSC 1953 color gamut as mapped against CIE 1931.

However, from the SID International Committee for Display Metrology’s (ICDM) recent, authoritative Display Measurement Standard:

“…we strongly encourage people to abandon the use of the 1931 CIE color diagram for determining the color gamut… The 1976 CIE (u',v') color diagram should be used instead. Unfortunately, many continue to use the (x,y) chromaticity values and the 1931 diagram for gamut areas.”

So why are there two standards, and why are we trying to declare one of them obsolete? Let me explain.

What is a color space?

First, a little background on color spaces and how they work.

While there are a number of different types of color spaces, we are specifically interested in chromaticity diagrams, which only measure color quality, independent of other factors like luminance. A color space is a uniform representation of visible light. It maps the all of the colors visible to the human eye onto an x-y grid and assigns them measureable values. This allows us to make uniform measurements and comparisons between colors, and offers certainty that images look the same from display to display when used to create color gamut standards.

In 1931, the Commission internationale de l’éclairage or CIE (International Commission on Illumination in English) defined the most commonly used color space. Here’s a look at the anatomy of the CIE 1931 color space:

What makes a good color space?

An effective color space should map with reasonable accuracy and consistancy to the human perception of color. Content creators want to be sure that the color they see on their display is the same color you see on your display.

This is where the CIE 1931 standard falls apart. Based on the work of David MacAdam in the 1940’s, we learn that the variance in percieved color, when mapped in the CIE 1931 color space, is not linear from color to color. In other words, if you show a group of people the same green, then map what they see against the CIE 1931 color space, they will report seeing a wide decprepancy of different hues of green. However, if you show the same group a blue image, there will be much more agreement on what color blue they are seeing.  This uneveness creates problems when trying to make uniform measurements with CIE 1931.

The result of MacAdam’s work is visualized by the MacAdam Elipses.  Each elipse represents the range of colors respondents reported seeing when shown a single color, which was the dot in the center of each elipse:

A better standard

It was not until 1976 that the CIE was able to settle on a significantly more linear color space. If we reproduce MacAdam’s work using the new standard, variations in percieve color are minimalized and the MacAdam’s Elipses mapped on a 1976 CIE diagram appear much more evenly sized and circular, as opposed to oblong. This makes color comparisons using CIE 1976 significantly more meaningful.

The difference of the CIE 1976 color space, particularly in blue and green, is immediately apparent. As an example, lets look at the color gamut measurements of the iPad 2 and new iPad we used in an earlier article. Both charts do a reasonably good job of conveying the new iPad’s increased gamut coverage at all three primaries. But, the 1976 chart captures the dramatic perceptual difference in blue (from aqua to deep blue) that you actually see when looking at the displays side by side:

The increased gamut of the new iPad is worth testing. Next time you find yourself in an Apple store, grab an iPad 2, hold it alongside a new iPad, Google up a color bar image and see the difference for yourself.

So, why do we still use CIE 1931 at all?  The only real answer is that old habits die hard.  The industry has relied on CIE 1931 since its inception, and change is coming slowly.

Fortunately, CIE 1931’s grip is loosening over time. The ICDM’s new measurement standard should eventually force all remaining stragglers to switch over to the more accurate 1976 standard. Until then, you can familiarize yourself with a decent color space conversion calculator, such as the handy converter we built just for this purpose:

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Apple's new iPad boasts better colors - how did they do it?

Back to share more of our display measurement results from the new iPad. Side note before we jump in: this is a somewhat technical post, if you aren’t familiar with the general workings of an LCD, this great live teardown by Bill Hammack is worth watching: http://youtu.be/jiejNAUwcQ8 There are two ways to improve the color gamut performance of an LCD display: you can either make the backlight better or the color filters better. In both approaches, the goal is the same: to make red, green and blue light as pure as possible. The LCD display mixes these three primary colors to make all the other colors you see on screen, thus, the more pure the individual pimary colors are, the better all colors on screen are.  Based on our measurements, it looks like Apple focused on the color filters for this new display, let’s take a closer look.

In the color spectrum chart below, you can see the result of some of the color filter changes that Apple made. Notice how the red peak (on the right, in the 600 nm range) has moved to a longer wavelength. This change in wavelength means reds on the new iPad will have a deeper hue, will be less orange and more distinctly red.

Another interesting thing to look at here is the blue peak at about 450 nanometers. In our last post, we noted that blue got the biggest boost with the new display. However, the blue peak did not change in wavelength or in shape, only amplitude (or brightness), which does not affect color. So what explains the dramatic improvement in blue seen on the new display?

The above spectrum isn’t telling the whole story. It was measured from a white screen, in other words a screen with all three primary colors turned on. We see very different results when looking at a screen with a blue image, where only the blue sub pixel filters are open.

This chart shows us only the light that is allowed to pass through the blue color filters. We can see the same blue peaks that we know from the white spectrum, but there’s also some extra light getting through - notice the two small tails to the right of the blue peak? That’s green light from the backlight leaking through the blue filter.

This means that when the iPad display needs blue light to make an image, some of that green comes along with the blue whether you want it or not. You will notice that the green blip is smaller on the new iPad, meaning less green is leaking through and a purer blue is displayed.  Take a look at the comparison shot here and you can see how just a hint of that green leakage is making the iPad 2’s blue (on left) appear slightly aqua by comparison.

Leakage like this happens because its very difficult to make a truly perfect color filter and even harder to make one that is efficient enough for a mobile display. The reason is basic physics – a better color filter is narrower, allowing only the desired color through.  However, the narrower you make the filter, the less light it lets through, and less light through means the display has to be driven harder to maintain brightness. This directly affects battery life, partially explaining the new iPad’s need for a larger battery.  Based on our experience, we estimate that the color improvements alone in the new display probably cause it to consume about 20-30% more power than the iPad 2's screen.

Perfecting the color performance of a display is a critical engineering challenge and worth highlighting because its one of those tiny details that Apple is so great at. Just making this small improvement in light leakage from iPad 2 to the new iPad accounts for a stunning amount of improvement in color performance and, most importantly, it makes for a richer user experience.

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Apple's new iPad display; what does 44% more color get you?

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Apple's new iPad display; what does 44% more color get you?

Last Friday Apple released an updated version of one of their hottest products, called simply “the new iPad.” Central to the update is a brand new display featuring significantly more resolution and color saturation. Since the resolution bit has been covered to death by others and we're interested in color here we thought we’d take a closer look at Apple’s color saturation claims. Our new iPad arrived on Friday and since then we’ve submitted it to several tests using our Photo Research PR 655 Spectroradiometer.

Using the new iPad, particularly next to an “iPad 2,” the reds and greens are noticeably better, but the blues in particular are quite striking. It actually makes the blue on the iPad 2 seem more ‘aqua’ than pure blue. The color data bears this out.  According to our measurements, Apple has significantly increased the saturation in all three primaries, most notably in blue:

The key color claim that Apple made on stage at the iPad announcement was that the new iPad has 44% more color saturation.  What they mean by that of course depends on the context.  There are a couple of different color measurement standards that Apple could be gauging the performance of the new iPad against such as CIE 1931 or CIE 1976.

An easy way to think about these standards is a bit like the temperature measures that we are all familiar with, Celsius and Fahrenheit, in that they are different ways communicating the same information. Saying, “it’s 5 degrees warmer today” means something very different to users of each system and its much the same way with color spaces, only we’re talking about measuring how the eye perceives color, not how warm it is outside.

We should also note that when people in the display industry talk about color saturation as a percentage, it is common practice to refer to a color gamut standard within a CIE color space. There are many color gamut standards in use today including: NTSC, sRGB, Adobe RGB 1998, DCI-P3, and rec 709. Each of these standards is a subset of a CIE color space. They are typically used by content creators to ensure the compatibility of their work from device to device. For example, if I create an image in Adobe RGB, I would like to display it on a screen that can show all of the colors in Adobe RGB in order to make sure it accurately reproduces all the colors in my original shot.

Based on our measurements it looks like Apple is referring to the NTSC gamut within a color space. But which color space do they mean?

A 44% improvement within the CIE 1931 color space would give the new iPad the equivalent of the sRGB standard used by HDTV broadcasts, Blu-Ray and much of the web. Given the significance of achieving that standard, some thought Apple must have been trying to say “sRGB” without confusing consumers by describing the meaning of various color standards.

According to our data, this is not the case. The new iPad only manages about 26% more saturation over the iPad 2 when measured against the CIE 1931 NTSC color space. However, the unit we measured showed a 48% increase in saturation when measured in the CIE 1976 color space, so that must be Apples frame of reference.

Measurements and standards aside, the new display looks great. The improvement in color performance will greatly enhance the user experience, and as we discussed yesterday, show’s what Apple is betting on for the functionality of future devices.

In our next post we will explain exactly how Apple achieved this improved color performance and look at ways they can improve the next generation.

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John Gruber on new iPad design compromises

Apple made the display a priority with its latest iPad release, breaking an unwritten rule that their products should get thinner and lighter with each release, not the other way around. John Gruber of daringfireball.net hit the nail on the head in his review of the new iPad:

Which brings us to an immovable object meeting an irresistible force. Apple doesn’t make new devices which get worse battery life than the version they’re replacing, but they also don’t make new devices that are thicker and heavier. LTE networking — and, I strongly suspect, the retina display3 — consume more power than do the 3G networking and non-retina display of the iPad 2. A three-way tug-of-war: 4G/LTE networking, battery life, thinness/weight. Something had to give. Thinness and weight lost: the iPad 3 gets 4G/LTE, battery life remains unchanged, and to achieve both of these Apple included a physically bigger battery, which in turn results in a new iPad that is slightly thicker (0.6 mm) and heavier (roughly 0.1 pound/50 grams, depending on the model).

50 grams and six-tenths of a millimeter are minor compromises, but compromises they are, and they betray Apple’s priorities: better to make the iPad slightly thicker and heavier than have battery life suffer slightly.

This point can't be understated. For Apple, the quality of the display, both in terms of resolution and color gamut, is so critical to the experience of using an iPad that they were willing to make some major tradeoffs. In this case they not only ended up with a slightly thicker, heavier device, they also used a significantly more expensive part. The end result is a stunning display that amplifies everything that was already great about the iPad 2 so it looks like a tradeoff worth making.

We took some color performance measurements of our new iPad this morning and we'll be posting more details shortly.

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CES 2012: more colorful displays on the horizon

If there is one thing we can take away from CES this year, it’s that displays with better color performance are on the horizon. Two of the largest attention getters at CES this year were new displays by Sony and LG.  LG unveiled a 55" OLED and Sony displayed a new “Crystal LED” technology.  While both of these displays exhibited impressive performance, including a wider color gamut, the Sony TV was a prototype only, and the LG display is expected to be available later in the year at a hefty price.

As Hubert of Ubergizmo points out, these technologies offer great promise, however, cost will be their determining factor.  OLED, which has been on the horizon for what seems like forever, still looks like it will not be available to the masses for quite a while, certainly not in large formats and not at a manageable price point for the consumer.

By contrast, QDEF, offers an affordable, consumer ready solution today. Display designers who are looking for the next new thing will find that they can have a screen with high brightness, deep color, high-DPI resolution and deep blacks in a display that's as big as they want using QDEF with no increase in cost. This is because QDEF has been designed as a drop-in diffuser sheet replacement to leverage the billions of dollars of existing installed manufacturing capacity and two-plus decades of improvements to LCD performance.  With QDEF, manufacturers can easily replace the diffuser sheet in their displays with a sheet of QDEF and gain over 100% of NTSC color performance.

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QDEF at CES 2012

I attended CES 2012 in Las Vegas earlier this month where I spent most of the week showing off a pair of QDEF-hacked iPads.  Also found some time got to check out some other high color performance display technology and I'll have more on that in a later post. For now, here's a quick review of a couple QDEF coverage highlights from CES: First up is a video interview I did with Bill Wong from Electronic Design. It was great to see these guys again and do a bit of deeper dive on the quantum dot nanotechnology that makes QDEF go:

EngineeringTV CES 2012 Interview

I also ran into Jaymi Heimbuch of Treehuger about QDEF’s ability to improve the performance of LCD displays while using less energy and requiring far less capex than OLED:

The technology is as energy efficient as LED technology, which means it is way ahead of OLEDs right now which offer beautiful displays but not necessarily a constant energy savings. In other words, while the future of OLEDs may seem bright (and companies like Samsung are still pursuing OLED displays while others like Sony have dropped out of the race), the future of LEDs is already here and the technology from Nanosys can mean vast improvements without much effort.

You can read the article in its entirety here: Treehugger.com

It was exciting to see the newest and best new technology available, and I can’t wait until we get to see some of these gadgets and electronic devices outfitted with QDEF displays.

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Record Smashing Sales of Video games like Activision’s Call of Duty will drive sales of high color gamut displays

If you ever doubted that video games are big business Activision's recent sales record should be enough to convince you. On its way to reaching $1 billion in sales in just over two weeks with Call of Duty: Modern Warfare 3, Activision smashed every entertainment sales record.

Every entertainment sales record.

That means books, movies and video games. Over its lifetime the franchise has generated in the neighborhood of $6 billion in revenue, which puts it squarely into a Star Wars-level stratosphere as one of the most valuable entertainment properties ever.

What does this have to do with high gamut color display technology?

One of the potential hurdles to widespread adoption of high color gamut display technologies is a lack of content that's optimized to take advantage of all those extra colors.

With Hollywood-sized blockbuster sales comes Hollywood-sized budgets to create rich new universes for gamers to explore. The expanded creative palette that high color gamut technology offers game developers is a perfect fit. What color is the blood of a martian supposed to be when it explodes and why limit it to a range of colors typically seen on earth?

Additionally, on the platform side, electronics manufacturers could take advantage of a push into high gamut displays to differentiate their entire hardware/software ecosystem. We already know that the current PlayStation™ hardware is capable of the xvColor high gamut standard. Pairing that with wide color games and a TV that can show it might prove a useful differentiator for any platform.

Videogames may just be the driving force that finally pushes high gamut displays into the mainstream.

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Test your color IQ

Xrite has kind of a fun "Color IQ Test" on their site- see how well you stack up against others in your gender/age bracket here

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Infographic: The Colorful History of Video Games

Great infographic that describes the history of color in videogames from colored cellophane overlays to millions of colors. The end of the graphic just hints at the next evolution in color for video games- wider gamuts that will give designers a whole new palette of colors to work with:

Via ColourLovers

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Quantum Dots Unleash High Color Gamut Performance in LED-Backlit Displays

This week I am featuring a guest blogger here– Jason Hartlove, CEO of Nanosys, the Palo Alto, CA-based maker of high color gamut-enabling display products. The following is a fairly in-depth, technical look at how and why Nanosys' quantum dot phosphor technology improves LED LCDs just by changing the color content of the backlight. Note: a shorter version of this article originally appeared in the October 2011 print edition of LEDs Magazine. LCD technology has made great progress in the past few years with innovations such as high resolution and 3D, yet color performance continues to lag. Displays on popular tablets can only express about 20 percent of the color a human eye can see; HDTV’s, only 35 percent. Surprisingly, color performance in displays has actually gone backwards since the days of CRTs.

Still, LED backlit LCDs have become the standard for the mobile devices and are fast becoming so for televisions due to their high resolution, low cost and thin form factors. According to Paul Semenza, Senior Vice President of DisplaySearch, a leading display market research firm, LED backlights will be used in 47.5% of LCD televisions and 98.4% of notebook PC displays shipped in 2011.

While new technologies with better color capabilities have emerged in recent years, such as discrete RGB LED, YAG with red phosphor and OLED, they face critical hurdles to mass adoption; primarily cost, scale and lower brightness. Until now, consumers have chosen cheaper, thinner and more efficient displays over a truly cinema-quality experience- but could they have it all?

What’s wrong with my current display?

To better understand the limitations faced by current TV and display makers, let’s take a look inside an LCD. For those who are not familiar, a typical LCD is made up of essentially two major parts: a light source, called the back light unit (or BLU) and a Liquid Crystal Module (or LCM). (See FIG. 1)

Usually, when a display is operating, the BLU is on, providing a uniform, white sheet of light behind the LCM. The LCM contains millions of pixels, each of which is split into sub pixels, typically with two green sub-pixels, one red and one blue. By controlling the amount of time each sub-pixel is “open” or allowing light to pass through it, and making use of the human eye’s persistence of vision, any color that can be rendered from a combination of red, green and blue can be displayed at each pixel location. Since the quality or fidelity of those colors is a direct function of the sub-pixel color quality, how good is the quality of red, green and blue light coming from each sub-pixel?

The color of each sub-pixel is a function of two things; the quality of the light in the BLU, and the color filter at the sub-pixel. The color filter will separate its component color from the white light of the BLU, for example, the red color filter on the red sub-pixels will cut off the green and blue light. However, to make a high quality color of red, either the filter function needs to be very narrow, which results in substantial attenuation and loss of brightness, or the red spectra in the BLU white light should be narrow and well matched to the desired peak red color. The same is true for the green and blue sub-pixels as well.

Since making perfect color filters is not practical from either a cost or brightness perspective, why not make a better white light?

The problem is, the LED light source at the heart of the BLU is starving those filters of the colors that they really need to shine. Today, white LEDs are very good at producing some of the spectrum of light that we see as ‘white’ but not all. While there are a variety of approaches for making white light from LEDs, the conventional approaches all suffer some drawback for LCD displays.

A YAG based white LED (i.e. Yttrium-Aluminum-Garnet phosphor pumped by an GaN blue source), produces a spectrum rich in blue with a broad yellow component. This light has very weak green and red content, and the spectra is widely distributed from aqua-marine through green, yellow, orange and red (see FIG. 2 below). When this light is filtered into the component RGB colors by the sub-pixels, the result is not accurate enough to produce the quality of color we see when we look at the natural world as illuminated by daylight.

So, an ideal light source for an LED LCD BLU would therefore be something in between daylight and two-color white. For vibrant colors, it would need to generate lots of energy across all of the red, green and blue wavelengths used by the filters. But, for efficiency’s sake, it should also not spend energy producing light between R, G and B because we just won’t see that light after its passed through the filters.

So how do we do THAT?

To solve the problems described above, what we need is a new class of material, not found naturally occurring anywhere on Earth, that can be tuned to emit light at just the right wavelengths for our displays and do so very efficiently. Fortunately, nanotechnology researchers have been working on designing just such a material for decades, building it literally one atom at a time, and Nanosys, a company in Palo Alto, California has perfected the art. Called “Quantum Dots”, the tiny, nanocrystal phosphors they make are a bit bigger than a water molecule but smaller than a virus in size.

Unlike conventional phosphor technologies such as YAG that emit with a fixed spectrum, quantum dots can be fabricated to convert light to nearly any color in the visible spectrum. Pumped with a blue source, such as the GaN LED, they can be made to emit at any wavelength beyond the pump source wavelength with very high efficiency (over 90% quantum yield) and with very narrow spectral distribution of only 30 – 40nm full width at half maximum (FWHM).

The real magic of quantum dots is in the ability to tune (at the fabrication stage) the color output of the dots, by carefully controlling the size of the crystals as they are synthesized so that their spectral peak output can be controlled within 2 nanometers to nearly any visible wavelength.

This capability makes quantum dots stand out against emerging iterations of YAG phosphor technology such as red phosphor doped YAG, which adds some red-emitting phosphor to the green-yellow emitting YAG to boost color performance. This idea is similar to quantum dot technology in that it attempts to engineer a spectrum of white light by combining materials with different emission spectra. However, these crystalline phosphor materials are still fundamentally limited by their atomic structure and therefore cannot be precisely tuned to match either existing color filter or manufacturers desired specifications. This leaves display manufacturers with a system that still results in light and efficiency losses due to the relatively wide FWHM output of the phosphors and poor conversion efficiencies and stabilities of red phosphors.

With quantum dot technology, display designers will have the ability to tune and match the backlight spectrum to the color filters. This means displays that are brighter, more efficient, and produce truly vibrant colors.

How does it all come together?

Engineering the quantum dots to precise display industry specifications isn’t enough on its own to revolutionize the way LCDs are experienced. The dots need to be easily integrated into current manufacturing operations with minimal impact on display system design if they are to be widely adopted. To do this, Nanosys spent a lot of time working with major display manufacturers to get the packaging just right so that it would be a simple, drop-in product that did not require any line retooling or process changes. The end result is called Quantum Dot Enhancement Film or QDEF.

Designed as a replacement for the an existing film in LCD backlights called the diffuser, QDEF combines red and green emitting quantum dots in a thin, optically clear sheet that emits white light when stimulated by blue light. (Of coursesome of that blue is allowed to pass through to make the B in RGB at the LCM). So manufacturers who’ve invested billions in plant and equipment for LCD production can simply slip this sheet into their process, change their ‘white’ LEDs to blue (the same LEDs but without the phosphor) and start producing LCD panels with the colors and efficiencies of the best OLEDs, at a fraction of the cost.

Nanosys is currently shipping production samples to display manufacturers and is on track to begin producing at commercial volumes by the end of 2011.

What does it look like?

The result is stunning color. A QDEF-enabled display can express over 60% of the spectrum a human eye can detect, compared with 20% for todays LED backlit LCD's. This means that browsing through photos on your tablet will be more like holding a stack of high quality, professional prints in your hand and watching a movie on the big screen in your living room is more akin to attending a private screening at a Hollywood studio.

LED backlit LCD TVs have established market dominance and tablet computers –which predominantly use LCDs– sales are expected to eclipse 100 million units over the next few years. Color is likely to be the next big differentiator in what is an increasingly cutthroat consumer display market as more players enter the market and alternative technologies are further developed.

Higher color performance displays will allow developers and content creators to create a stunning new visual experience for consumers. Display makers who can bring user experience closer to reality without sacrificing efficiency or cost will be able to establish a dominant market share.

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The difference between 'color gamut' and 'bit depth'

You’d be surprised at how often these two terms are used interchangeably in describing display performance. In fact, their recent misuse by a top display executive at a major consumer electronics company was one of the chief inspirations for this blog. Basically, it boils down to this:

  • More bits means more colors can be displayed
  • More gamut means more colors can be displayed

Got it yet?

While factually accurate, the statement above clearly illustrates the source of many a gamut vs bit depth misconception. Let’s dig a little deeper and define these terms.

First you should understand the simplicity with which modern displays create the color picture you are currently looking at.  Digital displays create all the colors you see by mixing just three primary colors, much like you did while finger painting in grade school. So, red plus green equals yellow, red plus blue is magenta and all three primaries combined creates white. 

Bit depth

So, what is bit depth? Bit depth refers to the number of bits that your computer uses to describe a specific color to your screen.  A typical modern display has “8-bit” color depth, which is a shorthand way of saying “8 bits of data per primary color.” Since 8 bits translates into 256 distinct values, your computer can call for 256 distinct hues of red, green and blue.

While ‘256’ does not sound like a lot of colors - it’s actually quite impressive. Mixing 256 reds with 256 greens and 256 blues (256 x 256 x 256), in a massive expansion of the finger painting analogy from above, creates nearly 16.8 million possible colors. Not too bad, right?

Well, you might ask, how many different colors can I actually see? Turns out a number of studies have been conducted on this, and most researchers agree that humans can detect anywhere between 7-10 million unique colors (see: http://physics.info/color/). This means that even a measly 8-bit display should have plenty of color accuracy headroom above and beyond the performance of your eyes.

So, a more accurate way to describe bit depth would be: more bits mean that a higher number of distinct colors can be displayed.

Gamut

If bit-depth refers to the number of distinct colors that can be displayed, where does that leave gamut? Perhaps the easiest way to think about gamut is as a measure of the range of colors that a display can show. Your 8-bit display may be able to show 16.8 million colors but that doesn’t tell you much about which colors. You see, not all reds, greens or blues are created equal.  When your computer calls for a specific color of deeply saturated red, for example, what you actually see is limited by the physical capabilities of the systems in your display.

How is gamut measured?

Color gamut performance is measured by a variety of standards, typically defined by groups like the National Television System Committee (NTSC) as a way of maintaining consistent color, from capture, to broadcast to end viewer. Creative professionals like graphic designers and Hollywood cinematographers rely on these standards to make sure that their work looks how they intended it to across a variety of screens and print media. The most common gamut standard, developed by the NTSC in 1953 in anticipation of color television, which is typically referred to as simply “NTSC,” covers about 50% of what your eye can see. 58 years and a couple generations of IPads later, we must be able to do better than that, right?

Unfortunately, unlike bit-depth, the color gamut performance of even high end, professional displays is still a far cry from the capability of your eye, which can detect wavelengths of light from 380nm to 740nm. Most high end displays can only display 25-35% of what your eye can see:

Putting it all together

Now we can put the two definitions together to clarify the oversimplification from the introduction:

  • More bits means more distinct colors can be displayed, within a range of colors that is defined by the display’s gamut

For a really in depth look at how color is displayed on your screen check out Steve Patterson’s very informative, much more in depth post on this topic over at photoshopessentials.com.

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