Picture Quality, Uniformity and Calibration

The INNOCN PU15-PRE is equipped with a 15.6-inch 10-bit OLED panel. The native resolution is 3,840x2,160, giving it a very high pixel density of 282 PPI, and a superbly sharp picture as a result. The panel is fairly glossy, so reflections could be a problem when the monitor is used in an area with a lot of light, especially outside. The viewing angles are fantastic. There's no color or contrast shift, even at extreme angles, so you're welcome to change your sitting position any way you like. This is a strong suit of OLED display technology and one of the best aspects of INNOCN's portable monitor.

Given the 15.6-inch screen diagonal, Windows recommends setting the monitor to 300% scaling. I found that a bit extreme because you're effectively losing a ton of screen real estate with that setting. The monitor is perfectly usable from a normal sitting distance at a 200% scale level. If your sight is good, you can go as low as 175%, perhaps even 150%, to get the highest possible amount of room for your apps and windows. You can't go below that, though, as everything becomes far too tiny.

In terms of picture quality, let me start by mentioning a strange (but completely fixable) issue I ran into when connecting the INNOCN PU15-PRE to my laptop through the HDMI interface. At first, I wasn't able to get anything remotely resembling that deep, OLED-specific black color. The blacks looked gray to my eyes, and my colorimeter agreed; the measured black luminance was 0.8024 cd/m², resulting in a pathetic static contrast ratio of 371:1. After some digging around the display settings, I realized that the problem was in the limited HDMI dynamic range (16-235), that my system defaulted to. After manually switching it to full (0-255), the blacks became truly black, so much so that it became impossible to determine where the picture ends and the physical edges of the screen start. When using USB-C as video input, the aforementioned issue wasn't present at all; it's entirely HDMI-specific.


At factory settings, the picture looks bright (367 cd/m² on my sample of the monitor), vibrant, and absolutely striking in terms of sharpness. However, a quick test with the X-Rite i1Display Pro colorimeter reveals notable color inaccuracies in the sRGB color space. The measured average ∆E is 4.02; the grays are decently accurate, but there are substantial deviations in various shades of red, green, and blue, spanning up to ∆E 9.59. The factory-adjusted white point is too high (6,789 K), but the OSD offers color temperature controls, so this issue can be fixed with a simple setting adjustment. Since the blacks on the PU15-PRE's OLED panel emit no light at all, the colorimeter showed an infinite static contrast ratio.


If you pick the sRGB color profile, you'll instantly get a significant improvement in color accuracy; the average ∆E drops to 2.13, with the largest deviation going from 9.59 to 3.38. However, the color temperature remains too high, sitting around 6.900 K. Using the sRGB mode locks you out of manually adjusting the color temperature, and the picture could look too washed out to an average user anyway, so for most owners of the PU15-PRE it's best to leave it on the default color profile and manually tweak it from there.

The color channel tweaks are extremely sensitive; changing a channel gain by only a single point (on a scale from 0 to 100) results in drastic changes to the resulting color temperature. Because of that, I found it best to set the color temperature to USER and lower the red and green channel gain to 49 while leaving the blue channel at the default value (50). I also suggest lowering the brightness, assuming you won't be using the monitor out in the open. Setting it to 61 will give you an output brightness of around 250 cd/m², which presents a nice balance between daytime and nighttime indoor usage.


Unfortunately, there's no way to improve gamma, as there are no gamma-related settings in the OSD. The actual gamma constantly stays ~0.2 above the referent value, which means that the panel is prone to crushing some of the dark detail, as it interprets shadows as darker than determined by the input signal. The only way to improve gamma is to do a proper hardware calibration of the monitor.


Of course, the color and luminance uniformity and the contrast deviation are terrific, as expected from an OLED panel.

Picture Quality After Calibration

After calibration, things fall into place, and the INNOCN PU15-PRE outputs very accurate colors with superb gamma tracking. The colors are noticeably punchier and even more vibrant than before; the panel becomes a joy to look at. The average ΔE dropped down to 0.39, and the maximum deviation was reduced to 1.33. In this state, the PU15-PRE could be used for more demanding tasks, such as photo and video editing, especially when we take into consideration its excellent color uniformity and contrast stability. The measured gamut volume is 173% for sRGB and 122.5% for DCI-P3 color spaces, with the gamut coverage measuring 100% for sRGB and 99.8% for DCI-P3, respectively. Outstanding!