A screen designed with sunlight in mind
Unfortunately, you won't see any of the Prime's spun aluminum skin when using the device as a tablet. Users face only the screen and its surrounding bezel, both of which are covered by a glossy piece of protective Gorilla Glass. This surface doesn't look bad right after it's been polished with the included microfiber cloth. However, it's impossible to use the tablet's touchscreen without leaving a mess of oily gesture remnants behind. Good luck trying to hold the thing without depositing a few thumbprints on the bezel.
While any smudges on the screen become almost invisible when the Prime is turned on, the glow has no effect on the surrounding bezel. The ring of greasy fingerprints circling the screen is a constant reminder of why glossy surfaces are less than ideal for devices that are handled frequently.
Reflectivity can also be an issue with glossy displays. The Prime's glossy screen coating seems to show a little less of myself staring back than the original Transformer. However, under normal indoor lighting, reflections are still clearly visible in darker sections of the screen. Turning up the tablet's brightness helps, and there's certainly plenty of luminosity on tap.
At its brightest, my first-gen Transformer cranks out a respectable 341 cd/m². The Prime pushes 407 cd/m² with its brightness turned up, and that's only the beginning. The TF201 also has a SuperIPS+ mode that ignites a small sun behind the panel. With this mode enabled, the screen delivers a whopping 643 cd/m² according to our colorimeter—an increase of nearly 60% over the normal config.
In direct sunlight, the Prime's extra luminosity makes it easier to use than the TF101. While the additional brightness definitely makes images clearer, they're still forced to share the screen with reflections of the surrounding environment. I wouldn't go so far as to call the Prime good for outdoor viewing, but it's definitely better than any other full-color tablet I've seen.
Like most tablets, the Prime features an IPS panel with better color reproduction than the TN displays found in typical notebooks. TN panels also tend to look washed out if you're not viewing them dead on, but the Prime's screen has wide 178° viewing angles, ensuring that colors remain vivid even when peering at the screen from a couple seats down on the couch.
Our first Transformer Prime sample arrived with an obvious yellow tinge to the screen; it was the first thing I noticed after turning on the tablet. That system was a pre-production unit never intended to go to the press, but the yellowish tint persisted in our second sample, albeit in muted form. As it turns out, Asus has deliberately tuned the Prime's panel to produce warmer colors than the original Transformer. Put the two tablets side by side, and the TF101's whites look a little bit blue, while the TF201's have a hint of yellow. The difference is difficult to capture on camera, so I busted out our colorimeter to profile the color gamut of each screen.
To make the two tablets easier to compare, the color gamut graph will switch between the Prime and first-gen Transformer when your mouse cursor is moved over the image. It takes a few seconds for the second image to load, so be patient.
Gamut graphs look intimidating, but our little mouseover effect makes the differences between the two tablets quite clear. The inner triangle that defines the Prime's color gamut is biased toward warmer tones, while the Transformer trends toward cooler colors. Note the intersection point at the center of each inner triangle. On the original Transformer, this point is closer to the D65 marker corresponding to the color temperature of typical daylight.
We can also isolate the color temperature of each display across multiple gray levels. The graph below has the same mouseover trickery as the one above, and the second image should be a little quicker to load. Here, we're looking for a color temperature of 6500K, which is equivalent to the D65 daylight illuminant from the gamut graph.
The Transformer comes much closer to the 6500K ideal for a few gray levels, but the Prime offers a more consistent color temperature across the entire range. Although I prefer cooler color temperatures in general, the Prime's warmer tones really only bother me when I'm switching back and forth with the old Transformer. Asus claims to be working with Google to add color controls to Android, but it doesn't sound like a done deal just yet. Being able to tweak the color levels of the display would certainly be a nice addition to the OS.
Temperature quirks aside, the Prime's screen is fantastic. Text looks crisp, the colors are lush, and the 1280x800 display resolution is a good fit for the 10.1" panel. This resolution serves up 30% more pixels than the 1024x768 screen on Apple's iPads, and the extra real estate is especially handy when the tablet is rotated in portrait mode. Now that I've figured out how to make the Android browser stop resizing text columns, I do almost all of my tablet browsing at 800x1280.