Brightness & Contrast
To read about our monitor tests in depth, please check out Display Testing Explained: How We Test Monitors and TVs.Brightness and Contrast testing is covered on page two.
Uncalibrated – Maximum Backlight Level
We could only find one touchscreen monitor in our database that is still available for sale: NEC’s E232WMT. The remaining screens are non-touch, business-class monitors, all with IPS panels. We have NEC’s EA245WMi, BenQ’s PD2700Q, Nixeus’ PRO Vue 27P, and Asus’ MG24UQ. That last one is a gaming monitor, we realize, but it is also a very competent 24” Ultra HD display that can perform a wide variety of tasks.
The P2418HT isn’t super bright, but it does provide enough output to get the job done. Its nearest competitor from NEC only offers an additional 30 nits, so it’s safe to say that the touch layer is a factor in overall luminance. Dell’s previous example, the P2714T, could only manage 271cd/m2. We recommend using any touchscreen in an indoor environment with no more than moderate overhead lighting. Tilting the panel upwards will catch reflections and wash out the picture.
The black level takes first place here at an impressive .2193cd/m2. That returns a contrast ratio of 1138.2:1, which makes it one of the better IPS displays we’ve reviewed. High contrast is a must for user interfaces that require you to discern small icons and buttons on the screen while still being able to read text clearly. Dell is using a quality panel here.
Uncalibrated – Minimum Backlight Level
It’s hard to imagine an environment where you'd want only 37 nits output from any monitor, much less a touchscreen. Even 50cd/m2 is pretty dim unless the room is completely dark. Nevertheless, our test shows consistent black levels and contrast throughout the entire luminance range in another nod to quality. We suspect that for most applications, users will have the backlight at or near its maximum.
After Calibration to 200cd/m2
That extra dynamic range comes in handy when pursuing the P2418HT’s maximum accuracy because we lost a little from our RGB and contrast slider adjustments. Now we’re down to 1000.5:1, but that’s still more than enough to keep the display in second place and well above its nearest competition, the E232WMT. Our adjustments were something of a compromise for ultimate color fidelity because we skewed gamma tracking a bit in the process. If you just adjust the RGB controls and leave contrast set to 75%, you’ll be closer to 1100:1. We’ll show you more detail in our gamma tests on the next page.
ANSI Contrast Ratio
Our sample suffered from hotspots along its bottom edge. That lowered ANSI contrast to 880.5:1. That’s still a respectable number but represents a 12% drop. We suspect other examples would measure better. You’ll also see the effect in our black field uniformity result on page five. It may sound like we’re complaining, but the P2418HT is still a quality monitor. Among all IPS monitors, it ranks well above average in our contrast tests. Picture quality is dynamic with good depth and detail.