Answers about the new iPad and Color

iPad2 gamut over iPad3 gamut

Please see the previous articles in this series:

Color Management and the iPad

Questions about the new iPad and Color

And for further information about iTunes and color conversion for iPads see:

More Answers about the iPad and Color

Apple described the gamut of the new iPad as “44 percent greater color saturation.” Which left us without much of a standard of comparison. After receiving an iPad3 today, I tested its color gamut, whitepoint, brightness, and screen detail against an iPad2. The graph above shows the increased color gamut. It also represents what I would call a “normalized” color gamut, in that the primaries are now more closely aligned to what we expect red, green, and blue to be. I haven’t attempted to do the math to see if the larger gamut is actually 44% larger, as this would only be for this specific iPad3, over this specific iPad2, so would not necessarily be representative in the way that the larger sample Apple could test would be. But it is significantly larger. Which has two noticeable effects: more saturated colors at the extremities, and different color in other areas which both tablets can reach.

sRGB gamut over iPad3 gamut

The second illustration shows the gamut of the new iPad with the gamut of the sRGB colorspace superimposed on it. I chose this order of layering, as there is more area in the iPad’s gamut that is outside of sRGB than the other way around, though as you can see at the bottom of the illustration, there is a sliver along what’s known as the purple line (from saturated red to saturated blue) where the new iPad does not appear to reach the limits of sRGB. On the red to green edge of the triangle, the match is excellent, and the mismatch on the green to blue edge is in the iPad’s favor; though without color management, no mismatch in any direction is actually favorable.

The ideal way to reproduce colors on a device is to have a larger than needed gamut, and to use color management to display the correct colors out of that larger range. The easy way to avoid color management is to attempt a one-to-one match between the two gamuts in question. The illustration above shows that Apple has gone for the easy fix, and created a screen with a gamut very close to sRGB. As long as the files sent to it are in sRGB, this should produce a reasonable match, certainly a much better match than the smaller and skewed gamut of the earlier iPads, and other iOS devices.

Viewing sample images on both iPads confirmed this effect. I first calibrated each iPad with a Spyder4, then viewed test images in the Datacolor SpyderGallery app, where the color profile can be turned on and off at will. The following are my comparison notes:

* With color management off on both screens, the color did not match between them. The iPad3 was considerably closer to matching the same image on a calibrated desktop display, however.

* Turning color management on made a big difference (as it has always done) on the iPad2.

* Turning color management on made a smaller difference on the iPad3; and often in the other direction.

* Matching between the iPad2 and iPad3 was excellent for in-gamut colors once color management had been turned on for both.

* Matching for out-of-gamut colors was closer, but not identical between them with color management.

* Yellows, in particular, look different on the iPad3 than on the iPad2, to the degree that memory colors, such as the logo color of SpyderGallery, look considerably different. Since there is no color management at the OS level, this cannot be corrected or changed.

*Density corrections in SpyderGallery still improve shadow detail on both iPad2 and iPad3; apparently there was not change in default gamma, even with the change in gamut.

* Default whitepoint on both iPads is very close; unlike the white points of my iPhone 4s versus my iPhone4, where the difference took some time to get used to.

*Maximum brightness of both iPads is, amazingly, identical. Earlier iOS devices have had a significant variation in max brightness, so its basically a coincidence that the iPad3 I received happened to be exactly as bright, today, as  my year old iPad2 is. My iPad2, when it was new, scored the highest brightness of any iOS device we tested, so having it still be as bright as a new iPad3 today is not surprising.

Next; the other factor that everyone has been waiting to hear about: the “retina display” screen. Let me start here by saying that an iPad 2 and an iPad3 are very similar to hold, with the weight difference being pretty much indistinguishable, and the difference in the lip profile minor. In your hands, the easiest way to tell which is which is by the larger camera filter on the back. On a desk, the easiest way to tell is by the slight thickness increase with the iPad3.

Given the degree of similarity, I mixed the two devices up repeatedly while handling them for comparison. So when I did my image detail comparison, it was truly a blind test, as I couldn’t even remember which iPad was which. The answer may not be what you are hoping to hear: the increased resolution is real, but not large. At 24 inch viewing distance or greater it is more or less indistinguishable (with good vision, or reading glasses to correct it). At 12 to 18 inch viewing distances, where close viewing of the iPad is more likely to occur, it is clearly discernible in type, but less so in images. Depending on where you images came from, and whether they were downsized for the iPad (as images coming in through iTunes are), there may be no difference at all. I expect that iTunes may start creating larger images for download to iOS devices. Certainly when viewing images from my Facebook library on both iPads, the resolution and compression Facebook has chosen for my images is low enough that there is no additional detail or sharpness with the iPad3. On images imported via the iPad Camera Connector, sharp and detailed images did indeed show sharper detail on the iPad3. You almost have to look for it to see it, but once you see it, its quite obvious.

So, my conclusion, which is surprising even to myself, is that the increased resolution in the iPad3 is nice, but not killer. While the increased gamut is much more noticeable. My second conclusion is that images on the iPad3 are closer to correct color automatically, thanks to the closer-to-sRGB screen gamut, while images viewed through SpyderGallery with a custom profile are more accurate still, though the difference is less with the iPad3 than it is with the iPad2. And my recommendation is that people  probably don’t need to run out and upgrade, unless they are using their iPads as photographic portfolios and other color critical uses, where the extra gamut, and closer match even in non-color-managed apps, matters more than in most other uses.

And as a footnote: The SpyderGallery wireless communication, calibration functions, color managed viewing functions, and remote viewing functions for Facebook and Flickr all seem to work excellently on the iPad3. I don’t anticipate any need to for an iPad3-specific update to the app.

Credits: C. David Tobie, Copyright 2012.   Website: CDTobie.com   Return to Blog’s Main Page