Tag Archives: Color gamut

Apple’s new iPad boasts better colors – how did they do it?

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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.

Blue color filter comparison: iPad 2 on left, new iPad on right

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.

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

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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.

John Gruber on new iPad design compromises

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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.

CES 2012: more colorful displays on the horizon

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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.

QDEF at CES 2012

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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.

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

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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.