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Results: Brightness And Contrast
To read about our monitor tests in-depth, please check out Display Testing Explained: How We Test Monitors and HDTVs. Brightness and Contrast testing is covered on page two.
Uncalibrated – Maximum Backlight Level
Today’s comparison group includes three other TN-based Ultra HD screens: Asus’ PB287Q, Dell’s P2815Q and Planar’s IX2850, which we reviewed a couple of weeks ago. Rounding out the charts are Sharp’s PN-K321 32-inch IGZO model and the excellent NEC EA244UHD 24-inch IPS display.
We were a bit surprised at the low maximum output number generated by the 288P6LJEB. As you can see, the other displays hit at least 300cd/m2, which is also supposed to be Philips' rating. We tried the other SmartImage modes, but found no additional light. While this won’t be a problem in a typical workspace, there isn’t enough brightness available for an outdoor location or a sunlit office.
Not surprisingly, the low backlight level means that Philips shows off the best maximum black level. Unfortunately, it does not mean you also get the best contrast.
A measurement of 776.3 to 1 is not the lowest contrast we’ve recorded for an Ultra HD screen. That distinction belongs to Dell's UP2414Q. It is lower than we’d like, however. Among the $600 4K screens, Dell and Asus have the largest dynamic range and therefore a little more pop than Philips.
Uncalibrated – Minimum Backlight Level
The 288P6LJEB’s backlight goes down to a perfectly usable 72.9868cd/m2. We’d prefer it to be closer to 50cd/m2, but 73-ish is still a good setting to use in darkened rooms. The 100-step brightness control has very fine resolution, so if you’re shooting for a particular number, it’s easy to hit it precisely.
Given the contrast numbers we’re seeing so far, we weren’t expecting a great black level result. It’s exacerbated by the higher-than-average minimum white level.
Minimum contrast is within a whisker of the maximum value, so the Philips is consistent at the very least. This is our ninth Ultra HD monitor review to date, and so far it seems that only Dell's UP3214Q tops a contrast ratio of 1000 to 1. Our hope is that next-gen AMVA panels will include 4K resolution so we can see ratios closer to 2000:1.
After Calibration to 200cd/m2
Calibrating the 288P6LJEB exposed a few obstacles, especially with regards to the contrast control. For that reason, we took a hit to overall contrast by adjusting the white balance and gamma controls. While a black level of .3088cd/m2 isn’t bad, it is the highest we’ve seen thus far from an Ultra HD display.
The calibrated contrast is correspondingly low at 646.8 to 1. We had to drop the contrast slider 12 clicks to correct grayscale issues at the 90- and 100-percent levels. This is a display where you have to decide whether to maximize contrast or achieve optimum accuracy throughout the entire brightness range.
ANSI Contrast Ratio
It’s rare that any monitor returns an ANSI contrast result higher than its calibrated one. We’re happy to see this because it means the 288P6LJEB’s image is of far higher quality than its on/off contrast results would indicate. After looking at all the numbers, we’d say the backlight control is where Philips stumbled a bit. If it could go a little brighter and return a slightly better black level, it would be perfect. There is obviously no problem with the panel’s grid polarizer, given the ANSI value.
