Introducing Wide Gamut Wednesdays

This week I’m kicking off a new series of posts that set out to answer a simple question:

“Can an HDTV accurately reproduce these colors?”

I’m calling the new weekly feature “Wide Color Gamut Wednesday” or #WideColorWednesday in social media speak. Each week we will analyze a new wide color gamut image and post the results to our @dot_color Twitter feed.

In the process, I think we’ll find that “wide gamut” colors – colors that fall outside the BT.709 color gamut used by HDTVs – are actually fairly common beyond classic examples like Brazilian tree frogs or Coca Cola cans. In fact, in our first test, we found a simple image of spring flowers, taken in Rochester, NY, contained mostly colors that fall outside the BT.709 gamut.

Wide Color Gamut image analysis

62.5% of the colors in this springtime flowers image fall outside the BT.709 color gamut used by HDTVs #WideGamutWednesday

I thought it would be helpful to write up the first #WideColorWednesday image as a blog post with some background on the process used to create these images.

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Are tennis balls yellow or green?

Tennis star Roger Federer’s answer to this seemingly innocuous question via twitter user @delaneyanndold caused a bit of a stir on social media earlier this week. According to Mr. Federer, tennis balls are very definitely yellow. He’s certainly an expert when it comes to tennis but how is his color accuracy? We applied some basic science to answer this important question once and for all. The answer might surprise you…

With his world-record 20 grand slam tennis championships, it’s likely few people on earth have spent more time looking at tennis balls than Roger Federer. He’s also backed up by the International Tennis Federation which has required all tennis balls be “yellow” in color for the last 46 years.

Case closed, team yellow for the win right?

Despite this overwhelming evidence in favor of yellow we still weren’t totally convinced. Reminiscent of the 2015 dress color controversy, Federer’s comment had Twitter users questioning reality. It turns out a large chunk of the population are totally shocked that tennis balls might be considered anything but green.

It’s understandable that Twitter users might be so passionate about this issue. After all, it can be a bit mind bending to think that much of the rest of the world sees such a common object as a completely different color.

So which is it? Are tennis balls green or yellow and, more importantly, why would we see them so differently? We had a hunch there might be more to this story so we set out to settle the debate once and for all with science

Yellow vs Green

Before we answer the question, we need to define the colors yellow and green so we know what we are looking for. There is broad agreement that humans perceive wavelengths of light from 520 to 560 nanometers as “green” and 560 to 590 nanometers as “yellow”.

Spectrum of Green and Yellow

According to our Physics textbook, “Fundamentals of Atmospheric Radiation,” the color green is defined as 520-560nm and yellow as 560nm-590nm.

These two colors are right on top of each other so, right away, it’s easy to see why there might be some confusion here.

Tennis Ball Color Measurement Nanosys

Capturing the spectra of a tennis ball with our Photo Research PR 655

With these wavelength ranges in mind for green and yellow, we grabbed our trusty spectroradiometer, our Wilson* Official US Open tennis ball, and captured some data. What we found when we plotted the data surprised us:

Tennis Ball Spectra

Measurement of light reflected from our tennis ball shows that the color is really green and yellow (or chartreuse). Shaded green and yellow regions represent generally accepted wavelength ranges for those colors.

Our original question turns out to be sort of a trick question. Tennis balls are neither green or yellow, they’re actually both green and yellow!

Looking at the data above, our tennis ball has a definite peak of reflected light at 525nm. 525nm is squarely in the green range but we would expect a pure green to have a bit more defined peak. Since we also see a significant amount of energy in the yellow range, a more accurate description of this tennis ball’s color might be “chartreuse” (link: https://en.wikipedia.org/wiki/Chartreuse_(color)) which lies right between green and yellow.

Why do so many people see tennis balls as either green or yellow?

The colors we see are determined by three things: the physical color of light reflected by an object, the physiological, electrochemical process of the eye to convert that light into an electrical impulse and the psychological, the processing the brain does to create an image from that signal. We already measured the physical component so it’s the last piece, the psychological that we’re most interested in in understanding why we might disagree about an object’s color.

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 and color-correcting the signal that comes out of our retinas.

One of the ways our collective brains may be influenced is by the appearance of tennis balls on TV. If tennis balls appear more yellow or more green on TV, that could shift our perception of the color. To find out if this might be a factor, we plotted our tennis ball into the CIE 1976 color space so we could compare it to a standard TV color gamut (if you’re not familiar with these charts, check out our primer on chromaticity diagrams).

Tennis ball vs TV Gamut.001

The “color gamut” of a tennis ball, plotted in CIE 1976. Left: tennis ball compared to HDTV BT.709 and UltraHD TV BT.2020 color gamuts; Right: zoomed-in view showing the tennis ball chromaticity is just outside the BT.709 color gamut

Here we see that the tennis ball is a very saturated color that lies right between green and yellow. It’s also interesting that our tennis ball is right on the edge of the BT.709 color gamut used in HDTV broadcast. In fact, if we take a closer look at the zoomed-in chart on the right, the tennis ball is just outside the range of colors used by HDTVs.

Displays cannot simply recreate the exact spectra of light reflected off of a tennis ball that we measured above because displays create color through a totally different process called additive mixing. Displays mix just three primary colors of light (red, green and blue) to recreate millions of colors. In the case of a tennis ball, a display essentially tricks our eyes into seeing chartreuse, by mixing together red and green light. The quality of chartreuse that a display can reproduce is therefore determined by the quality of red and green light a display can reproduce.

Since the tennis ball falls outside the primary colors of the HDTV broadcast signal, this means that the color of a tennis ball is essentially impossible to accurately reproduce on a standard HDTV. Additionally, most HDTVs would not have the correct red and green to recreate our exact shade of chartreuse. As a result, the actual color that most TV viewers experience is based more on the creative decisions of broadcast crews and the color gamut mapping algorithm of their TV, which may be shifting the color more towards yellow.

If that’s the case, it would help explain why so many of us perceive tennis balls as yellow. That’s because they are yellow when they mean the most to us, which is on TV during an important match. This doesn’t quite explain Federer’s perception. Although it is quite possible that he’s watched enough endless hours of film working to improve his game, which he likely cares deeply about, to have shifted his view towards yellow.

It will be interesting to see if our collective tennis ball color perception begins to shift towards green or chartreuse as more and more people adopt UltraHD TVs with wide color gamut capabilities.

*: Note that we chose to use a Wilson ball since it’s the official ball of the US Open and we’re based in the US. As a future experiment, it might be interesting to test the ball used at other events like Wimbledon to see if there’s any international variance in color.

Special thanks to Ernie Lee and Brian Mui!

Watching the World Cup finals this weekend? Your HDTV probably can’t show off Messi’s boots in all their bright blue glory

Lionel Messi laces up some bright blue boots- these super saturated Adidas Sambas were designed for the FIFA World Cup 2014 (image source: Adidas)

Lionel Messi laces up some bright blue boots- these super saturated Adidas Sambas were designed for the FIFA World Cup 2014 (image source: Adidas)

If you’ve been following the FIFA World Cup this summer you may have noticed many players wearing some seriously colorful cleats. These super saturated Sambas are part of a new line-up specially designed by Adidas for the 2014 FIFA World Cup. They are being worn by many of the game’s top players like Argentina’s Lionel Messi who will be wearing his bright blue boots during the finals this weekend.

What you may not know is that, as wild as these shoes appear on your TV, you are actually not getting the whole picture. Today’s HDTV’s are only able to reproduce a limited range of colors- only about a third of what your eye can see- so there’s a lot missing. Common colors from the red of a London bus to Pantone’s color of the year fall outside this small range and watching the games over the past few weeks I’ve been thinking these shoes are also likely to be too colorful for TV.

The horseshoe shaped chart above represents the range of colors that our eyes can see and the triangle contains all the colors an HDTV can show. Lionel Messi's blue cleats fall well outside that range so the color you see on your TV is not accurate.

The horseshoe shaped chart above represents the range of colors that our eyes can see and the triangle contains all the colors an HDTV can show. Lionel Messi’s blue cleats fall well outside that range so the color you see on your TV is not accurate.

So, in honor of this weekend’s World Cup final, I got my hands on a pair of boots that matched my favorite player, Messi’s, and took some measurements to see what I’d find. Turns out that deeply saturated blue falls well outside the range of colors that HDTV’s can produce.

You may not be able to see those blue boots in their full glory unless you are at the stadium but, if the semi-finals are any indication, this weekend’s games should still be pretty exciting to watch!

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.

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.

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).

US Wrestler Jake Varner (red) on his way to defeating Valerie Andriisteve of Ukraine in the 96-kg freestyle wrestling gold match in London. Credit: The ASSOCIATED PRESS

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.

Even on Mars, color matters

One of the most important pieces of equipment on the Curiosity rover is not a spectrometer or a laser but a color calibration chart. Nothing is simple when you’re sending a robot on a 354 million mile journey into space, but NASA and Bill Nye (yes, the “science guy”) came up with an ingenious solution to calibrate the colors of the onboard cameras.

In order for NASA scientists to be sure that we are seeing “The Red Planet“ in the correct shade of red, they attached red, green and blue color chips to a sundial on the surface of the rover. These reference colors will guarantee the amazing photos we are seeing of the Martian landscape are accurate.

Here is an animated gif of the sundial on the surface of Mars and a close-up shot of it before it left Earth:

Can your TV accurately display your favorite NFL team’s colors?

Over the weekend I saw this interesting tweet about color gamut and the NFL and I had to find out if it was true:

Could it be that something as simple as an NFL jersey is not within the color gamut of modern HDTVs? I mapped the Broncos team colors onto the CIE 1976 color space along with the HDTV color gamut standard, called rec.709. As you can see, the orange is right on the edge and the blue is indeed outside the gamut.

When we think of high color content, we think of action movies and video games, but this exemplifies how color performance affects everything we see on our TVs, even down to the jersey being worn by our favorite sports team. Luckily high color displays are on their way to fix this problem.  As you can see, the Bronco’s colors fall nicely within the much wider DCI-P3 color gamut.

Is creativity the next killer mobile app?

Since the debut of the iPad in 2010, tablets have become the ultimate content consumption device, but many still to wonder if they’ll ever be capable of replacing notebooks for portable content creation.

While tablets may never truly replace notebooks for all of our content creation needs, especially typing intensive ones, a new crop of apps for iOS and Android are certainly making a case for it.

A little doodle made with the glorious new #Paper app for the iPad from @FiftyThree

(via Brian Taylor from CandyKiller: A little doodle made with the glorious new #Paper app)

Recent creative apps like Paper by fiftythree, Adobe’s Photoshop Touch and Apple’s iPhoto for iOS have just started to scratch the surface of the creative capabilities of powerful mobile devices. These apps show us that mobile creativity, when done right, can harness the unique properties of a touchscreen handheld device to offer new capabilities that a laptop cannot duplicate. Drawing with a stylus in Paper, for example, feels remarkably precise and expressive because of a neat gesture trick- the speed of your pen controls the thickness of the line. Similarly, in Photoshop Touch and iPhoto, editing your photos by actually putting your hands on them, while less precise than a keyboard and mouse, can be a revelation for broad stroke tasks like blending two images.

Tablets clearly have the processing power, the battery life and display resolution necessary to become serious creative tools, but there’s one thing missing: color. Creative professionals normally work on displays capable of showing a range of colors that is as much as 60% wider than even the latest “high color saturation” iPad. Artists need to see the content they are creating in the same vibrant colors they see in the real world.  Improving the color performance on mobile devices will make tablets truly worthy of a place in any creative professional’s regular workflow.