How much color gamut do displays really need? Part 2: How we perceive color

Last week I set out to define the ultimate consumer display experience in terms of color performance. I laid out some potential color performance design goals for an ideal display, suggesting that such a display should be both accurate and capable of creating an exciting, immersive experience that jumps off the shelf at retail.

Can we achieve both goals? To find out, let’s start by looking at how we perceive color.

Color Perception

The color of objects that our eyes see in nature is determined by three things: physical, physiological and psychological:

The color of objects that our eyes see in nature is determined by three things: physical, physiological and psychological.

The color of objects that our eyes see in nature is determined by three things: physical, physiological and psychological.

The physical component of our color perception is a constant based on the laws of nature. It is a combination of the quality of the illumination or light source, in this case meaning spectrum it contains, and the reflectance of the object. In the image above, the ball appears red to the eye because it is reflecting red light, while absorbing most the other colors from the light source.

The physiological part of our vision is also a relative constant that is based on the electrochemical processes of the eye. The back of the retina contains photoreceptor nerve cells which transform incoming light into electrical impulses. These electrical impulses are sent to the optic nerve of the eye and onto the brain, which processes and creates the image we see. And that’s where the psychological component comes in.

Let’s look at how each of these components might affect display color performance, starting with the physical, which ought to be something we can measure.

Physical

Fortunately, a guy named Pointer has done this for us. For his 1980 publication, Pointer measured over 4,000 samples and was able to define a color gamut of real surface colors, of objects found in nature. The result is commonly called “Pointer’s Gamut:”

Color gamut of 4,000 surface colors found in nature as measured by Pointer in 1980 against the color gamut of the iPhone 5.

Color gamut of over 4,000 colors found in nature as measured by Pointer against the color gamut of the iPhone 5.

This already seems like a great place to start. It immediately looks like a great fit our first ultimate color experience criteria which was accuracy. If we could accurately capture and reproduce all of the colors found in the natural world it would make for a much improved, more accurate ecommerce experience, for example.

But how important are those extra colors? Looking at Pointer’s gamut mapped against the color gamut of the latest iPhone in the chart above, you have to wonder if we really come across these deep cyans and reds in everyday life. Are they just infrequent, rare colors or something worth pursuing for our display?

Turns out we do. As an example, Pantone’s color of the year for 2012 was a deep emerald green that falls outside of both the iPhone’s gamut and the HDTV broadcast standard. This is an important and popular color that appears a bit too yellowish on your computer monitor when you are shopping for the perfect tie on Amazon. So there are some really important colors outside of what the iPhone can display today.

But, what about our second criteria, the lifelike, exciting, immersive experience we want to give consumers? Is the gamut of the natural world enough?

Physiological

If we look at the second component of the visual system, the physiological component, we’ll see that we can actually perceive a much wider range of colors. The cells in the back of retina can actually detect the entire range of the CIE diagram. That’s almost double the range of colors that Pointer found in nature:

Color gamut of the average human eye vs gamut of colors found in nature as measured by Pointer

Color gamut of the average human eye vs gamut of colors found in nature as measured by Pointer

This is starting to sound like a much more immersive experience. Maybe we ought to pursue the full color capability of the human eye just like the industry has done for high, “retina” resolutions.

It sounds great but it would be a tall order. It would take quite a lot of power, brightness and extra bit depth to even begin to think about covering a color space this large. There certainly would be a high price to pay in terms of design tradeoffs to get there. So are there any truly valuable colors contained in that extra space, similar to the Pantone color in Pointer’s gamut, that would make us want to go for it?

Psychological

This is where the psychological component comes into play.

Seeing is not passive. Our brains add meaning to the light that our eyes detect based on context and experience and memory. We are continuously and actively re-visualizing the light that comes out of our retinas.

This may seem hard to believe but this fun demo created by neuroscientist Beau Lotto does a great job of showing just how much our brains actively interpret and change what we see.

The color of the chips has not changed in the video above, just our perception of the color. What’s happening here is our experience is telling us that the color chip in shadow must actually be a much brighter color than the chip under direct illumination, so our brain is just making the correction for us on the fly.

Artists absolutely play on this psychological element of our perception of color, sometimes using totally unrealistic or hyper real colors to make us feel or experience something new or help tell a story. In fact, one of the most influential art instructors of the 20th century, Josef Albers, once said that, “the purpose of art is not to represent nature but instead to re-present it.”

Monet's The Poppy Field, near Argenteuil

Monet’s The Poppy Field, near Argenteuil

So, whether it’s Monet using saturated and contrasting colors with equal luminance to trick our brains into seeing poppy flowers sway in an imaginary breeze in a 19th century painting or modern films which sometimes rely on the wider gamut capabilities of color film and digital cinema projection to create uniquely cinematic experiences for audiences.

Movies like “The Ring,” for example, which used a deep cyan cast throughout much of the film to create tension and help tell a scary story. Or Michael Bay’s “Transformers” movies, which use deeply saturated oranges, reds and teal greens to create an exciting, eye-popping palette appropriate for a summer blockbuster sci-fi movie about giant robots:

Wide color gamut in movies

There’s certainly a place for wild, unexpected colors in art. But, as we go through some of these examples, I think we’ll actually find that there is a huge range of expression possible within the gamut of surface colors that Pointer measured. The full range of gamut detectable by the human eye, while exciting to think about, is not really necessary to deliver both accurate and pleasing (engaging) color to our visual system.

So where does that leave us?

In my next post I’ll look at existing wide color gamut standards and content delivery mechanisms to see both what we can do today and what’s next for wide color gamut displays.

Adobe’s Kuler color app is a great tool for designers but is your display accurate enough for it?

Screenshot of Adobe's Kuler app showing color extraction from a photo

Screenshot of Adobe’s Kuler app showing color extraction from a photo

Adobe recently released a new iPhone app called Kuler that let’s you extract colors from your surroundings using the phone’s camera. It’s a useful tool that allows designers to capture color inspiration wherever they find it and easily incorporate it into their work via color palettes.

The app also highlights a weakness in current display technology: no display on the market today can actually reproduce all the colors we see in the environment around us. So, even if the camera sensor can capture that color you love, you may not be seeing an accurate representation of it on your device.

The iPhone 5’s LCD display is designed to cover the sRGB/rec.709 color gamut standard used for HDTV broadcasts. And, it looks great but compared to the world we see around us, it’s just not quite as rich. If we plot the iPhone 5’s color gamut against the gamut of colors found in nature, the phone comes up short in important reds, greens and cyans:

Color gamut of the iPhone 5's display compared to the gamut of colors found in nature. The iPhone 5 comes up short in red, green and cyan.

Color gamut of the iPhone 5’s display compared to the gamut of colors found in nature. The iPhone 5 comes up short in red, green and cyan.

If DisplayWeek 2013 was any indication, color has once again become a hot topic in the display industry. Color gamuts are getting larger and it may not be long before we see a display that can match what our eye sees in nature. Over the course of the next year, we will start to see more wide color gamut-capable devices as OLED continues to expand marketshare and new technologies like quantum dot LCD begin to enter the market in volume.

DisplayWeek 2013: Color is back

Just back from a great DisplayWeek in Vancouver. Finally had a chance to recover, go through my notes and process everything I saw at the show. Most of the big story lines will be pretty familiar to anyone who followed last years show: TV’s are still getting bigger, OLED TV is still right around the corner, 4K is starting to ship and mobile displays are getting both sharper and more efficient.

DisplayWeek wasn’t all old news though. In fact, just like CES, this year everyone seemed to be talking about color performance. At the annual Display Industry Awards, honors in several categories went to wide gamut display technologies including the Best In Show and Component of the Year awards. And, on the show floor, major manufacturers like 3M, Samsung and LG dedicated significant booth space to wide color gamut or color management technologies.

3M's Quantum Dot Enhancement Film demo at DisplayWeek 2013. Bottom display is using quantum dots to achieve a wide color gamut.

3M’s Quantum Dot Enhancement Film (QDEF) demo at DisplayWeek 2013. Bottom display is using quantum dots to achieve a wider color gamut than OLED at higher brightness and lower cost.

3M demoed several wide color gamut LCDs  based on the Quantum Dot Enhancement Film (QDEF) technology that they are partnering with Nanosys to manufacture. Ranging from smartphone all the way up to 55″ TVs in size, these devices were all showing a wider color gamut than OLED with an especially deep red. This seems like a lot of color but 3M says that in developing their Perceptual Quality Metric (PQM), a new analysis tool aimed at helping display makers model how different performance characteristics will affect end user experience, they found that color saturation positively affected the perception of quality.

In Samsung’s neighboring booth, I found a series of comparison demos designed to show that wide color gamut displays can be both accurate and pleasing to the eye. Each demo featured a camera feeding a live image of several colored objects to both standard and wide color gamut displays. In each case the wide gamut display was able to more accurately recreate the color of the objects in front of the camera. They also showed off the new color management capability of their flagship Galaxy S4 smartphone that allows the device to accurately display rec.709 content without oversaturation- something the previous generation S3 struggled with.

Samsung demonstrating the value of wide gamut displays by showing some common colors that fall outside the rec.709 broadcast gamut standard in a series of demos at DisplayWeek 2013

Samsung demonstrating the value of wide gamut displays by showing some common colors that fall outside the rec.709 broadcast gamut standard in a series of demos at DisplayWeek 2013

Finally, at LG’s booth, we saw a new LCD color filter design that allows them to cover the Adobe RGB color gamut used by photographers and print professionals.

With all of this buzz, it looks like we’ll start to see wide color gamut displays start to move into the mainstream in ever larger screen sizes over the next half of this year and into 2014.

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.

Apple CEO Tim Cook talks color quality at Goldman Sachs conference

Apple CEO Tim Cook

Apple CEO Tim Cook spoke at Goldman Sachs’ Technology and Internet Conference yesterday. He touched on a wide range of topics from what Apple plans to do with its cash horde to the state of its retail operation. When it came to a question about making lower cost products, Tim used display quality to help make a point about creating great user experiences:

The truth is, customers want a great experience and they want quality and they want that a-ha moment each time that they use the product, and that’s rarely a function of any of those things.

If you look at displays, some people are focused on size. There’s a few other things about the display that are important. Some people use displays, like OLED displays, the color saturation is awful. And so if you ever buy anything online and you want to really know what the color is as many people do, you should really think twice before you depend on the color of the OLED display. The Retina display is twice as bright as an OLED display. I only bring these points up to say there are many attributes to the display, and what Apple does is sweat every detail.

He makes some fair points here. If a display is not bright enough to view in all conditions, not efficient enough to get you through a whole day or accurate enough to display your favorite content, the experience of the whole device suffers. Choosing the right display technology is certainly a critical part of the design process.

OLED technology’s power consumption and saturation issues have been well established already. What I find most interesting in Tim’s comments is the idea that high color saturation is intrinsically a bad experience. It certainly has been that way so far but the difference between a great color experience and the gaudy oversaturation of today’s OLEDs is in exactly the kind of implementation details he’s describing above.

OLED and emerging LCD technologies, like quantum dot displays, can actually show a much wider range of colors than today’s devices– over 40% more of the color that our eyes can detect. This means that, when paired with the right content, high saturation displays can more accurately reflect the world we see around us resulting in a more lifelike, immersive experience.

But how do we get wide color gamut content into consumers hands?

It’s a lot like the chicken and egg/content and technology dilemma facing 4K TV makers with two key differences- wide color gamut can be delivered with no change in file size and there’s plenty content out there already. As an example, movies have been shot for decades on media, both film and digital, that has a much wider color gamut than your TV does today. Much in the same way that 4K TV’s can upscale HD video, it’s also relatively easy to manage the color on a device to make it backwards compatible with today’s content.

OLED implementers have thus far been content to take advantage of the extra pop that added color saturation provides when comparing devices on a store shelf. They’ve left a tremendous amount of overall ecosystem value on the table. It’s possible to deliver video in cinema-level color quality to mobile devices, to offer developers the tools to take full advantage of a wider color palette and to implement accurate color management for existing content. Wide color gamut is ready now, it’s just waiting for the right device maker to come along and put all these pieces together to perfect the experience. 

Color at CES 2013

I’m just wrapping up my visit to CES and it’s been interesting year for display technologies. Amid all the noise about 4K, OLED and 4K-OLED, color performance seems to have quietly worked its way into the conversation. I can’t recall ever having so many relatively technical conversations about color with booth reps from major consumer electronics manufacturers at a CES. It nearly started feeling like a visit to DisplayWeek, that is until I ran into some of the weird, only-at-CES iPhone cases

Color Your World CES 2013

I bet we’ll see more color talk next year, especially as 4K content delivery mechanisms and standards begin to mature. In the meantime, these are some of the color-related display stories that caught my eye this week:

Wide gamut content delivery

Sony’s 4K content delivery plans have been one of the most talked about topics here at CES. Less mentioned was Sony’s inclusion of wider color gamut in their standard. Sony reps that I talked to said that both the 1080P Blu-ray disc-based “mastered in 4K” and pure 4K delivery methods would include a wider color gamut. They were not ready to release specifics on gamut size or whether it would meet existing standards like DCI-P3. Still, bringing “expanded color showcasing more of the wide range of rich color contained in the original source” is a move in the right direction for wide gamut.

Color accuracy

Technicolor showed off a color certification program that they hope will incentivize display makers to improve the color accuracy of their panels. Displays that meet or exceed Technicolor’s color specs will get a badge and a copy of partner Portrait Display’s Chroma Tune software, which dynamically controls color gamut to match the application you are using. This means if you open Photoshop on a device with an Adobe RGB 1998 capable display, you’ll get the full, wide gamut. But, if you switch over to watch a YouTube video in your browser, the software will limit the display to rec.709 for the most accurate experience. The advantage was well demonstrated by their e-commerce demo, where a pair of shoes were more accurately depicted on a certified display:

Technicolor's ecommerce Color Certification demo at CES 2013. The color certified laptop in the middle of the frame more accurately shows the color of the shoes.

Technicolor’s ecommerce Color Certification demo at CES 2013. The color certified laptop in the middle of the frame more accurately shows the color of the shoes.

Like Sony’s upscaling effort, this kind of technology could help drive wide color gamut adoption by making today’s content compatible with newer displays.

Huge tablets

Panasonic 4K Tablet with sRGB color gamut at CES 2013

Panasonic’s 20 inch 4K/sRGB tablet

Several companies at the show introduced devices in a new class- the 20-plus inch tablet. While there were a lot of hokey multi touch gaming demos (are you really going to play poker with 4 smartphones and a 27″ screen instead of a deck of cards?), the content creation stuff Panasonic showed actually made me think the new form factor shows real promise as a professional tool.

Their tablet, which measures 20 inches on the diagonal, features a 4K IPS panel that covers 100% of the sRGB color gamut standard. Having such a a large canvas with high resolution, accurate color and multi-touch could be great for creative pros like photographers and architects.

Color of the year for 2013 falls outside sRGB gamut

Pantone Emerald 17-5641

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.

Based on data from Pantone’s website, I was able to plot the color in CIE 1931 (xy). As you can see in the chart below, Pantone’s color is well outside the sRGB/rec.709 color gamut standard used by most HDTVs, the new iPad/iPhone and many desktop monitors. These devices will be stuck showing a version of Pantone’s emerald green that’s less saturated and probably a bit more yellow than the real thing.

Pantone Emerald 17-5641 vs sRGB, Adobe RGB 1998 and DCI-P3 color gamuts in CIE 1931

This is a perfect example of a popular real-world color that falls outside of the sRGB/rec.709 gamut. Unless you have a monitor that’s able to show wider color gamuts, like the DCI-P3 or Adobe RGB standards, you are missing out on a great color.

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.

Shopping for a tablet this holiday season? Don’t forget to look at color performance

If you have been researching the perfect tablet to give to a loved one this holiday season, you’ve probably read a lot about display quality. Tablet display size, resolution and aspect ratio have been discussed at length this year, which is really no surprise, since the quality of the display has the biggest impact on how we enjoy content on these devices.

What is surprising though is that color performance, one of the biggest differentiators among the current crop of tablet displays, has been largely glossed over by the mainstream gadget press.

The Verge’s tablet comparison tool, for example, gives great info about pixel density, aspect ratio and touch capabilities, but color performance is nowhere to be found:

Color is being ignored in spite of the fact that there are tremendous differences in the color performance of each of these devices that directly impact the consumer experience on each.

So why are we overlooking a feature that, unlike many of the features we focus on these days, presents a real difference between devices?  I see a couple reasons. First and foremost, thanks to Apple’s marketing of the Retina display, pixels-per-inch has become the spec du jour in today’s device wars.  Device makers are focusing their marketing efforts on pixel count above anything else.

Aside from current trends, I believe there’s also a macro reason to why color has been left out: color performance is just hard to compare. There is no universally accepted spec that can sum up color performance across devices.

Take the three popular tablets above. We could add a “color gamut” row to the chart, measuring against sRGB, which would look like this:

From this information, a shopper could gather that the Nexus 7 and Kindle Fire HD have about the same color performance and both outdo the iPad mini. That is an accurate assessment, but it’s not the whole story. If we look at those color gamuts plotted in CIE 1976, some important nuances become apparent.

By measuring the percent of sRGB, we know how much of that overall color standard the device can reproduce.  However, displays usually produce more of one color than another and that information is completely lost with this measurement.  The Nexus and Kindle have significantly deeper blue than the iPad mini, most likely due to a narrower blue color filter like the one found in the third and fourth generation iPad. This accounts for most of the difference in sRGB coverage between the iPad mini and the other two devices.

Take a look at the other two primaries and it gets more interesting. In the image on the right that zooms in on green, we see that the Kindle Fire has the deepest green of the three, followed by the iPad mini and the Nexus.

For reds, though, it’s different again, with the Nexus having the deepest reds followed by Kindle and then iPad.

If we ever want to make color performance a real differentiator in consumer choice, we need to develop a new universal standard to easily compare color across devices, taking into account all of these nuances.

Color is a complex story to tell, but small differences in color performance are just as noticeable to consumers as pixel density in everyday use. Next time you find yourself at a retailer who carries all three devices, try googling test patterns and look at the differences. You might be surprised.

Gizmodo: Tech’s New Most Meaningless Spec: PPI

source: Gizmodo

Adrian Covert of Gizmodo has an interesting piece looking at the gadget industry’s recent obsession with high PPI displays. With devices like the HTC DNA pushing resolution well past 300 PPI, electronics makers may be turning PPI into the next overhyped marketing stat, just like contrast ratio is for the TV industry and megapixel is for the digital camera.

Adrian gets to the heart of the problem:

There are plenty of ways to make a better-looking display. But we’ve reached the point in the pixel density wars where higher figures have stopped automatically equating to improved performance for users. Any grandstanding about pixel density, from here on out, now is mostly just marketing fluff.

We tend to agree, and color performance is probably the display feature with the most room to improve. The best LCD smartphones on the shelves right now can show you more pixels than your eye can detect, but can only show you about a third of the colors you can see. If electronics makers want impactful feature improvements for new devices, color performance is where it’s at.