Grayscale, Gamma & Color
The U3818DW can be used in its Standard color mode without adjustment. It meets the calibration numbers printed on the included data sheet and is accurate enough for most critical tasks. To maximize performance, choose the Custom Color mode and tweak the grayscale as we did.
Our grayscale and gamma tests are described in detail here.
Grayscale errors in Standard run ever-so-slightly green at the 80-100% levels. If we hadn’t told you about it, you’d likely not see it. The U3818DW easily qualifies for our “doesn’t need calibration” list.
If you wish to tweak the Custom Color mode, you’re committed to adjusting the RGB gains, because green errors are more visible. The average Delta E jumps to 3.41; not too high, but enough to be seen. The sliders are extremely precise, and after lowering the contrast control, we got all errors under 2dE. This is excellent performance and we think it’s worth making the changes despite a loss of dynamic range.
2.34dE for the Standard mode puts the U3818DW in step with the other displays here except for BenQ, which has amazing out-of-box accuracy. That’s why the PD3200U has become our reference monitor. None of the panels here need calibration, but given their intended use, it wouldn’t make sense to ignore that last tiny bit of performance.
Calibration brings the U3818DW to the professional level with a .75dE average grayscale error. It doesn’t get much better, and at this point the difference between all the monitors is negligible except for the BM320, which is unchanged from its default state.
The U3818DW’s gamma is nearly spot-on regardless of mode or adjustment. In Standard, there’s only a small aberration at 10%, which is a little too bright. This helps bring out shadow detail, but it also reduces perceived contrast. Switching to Custom smooths out the trace and after tweaking the RGB sliders only shows a slight dip at 90%. Overall contrast is lower than average, but solid gamma like this helps improve color and overall image quality.
Aside from the AOC monitor, gamma performance is pretty much the same from all screens in the group. LG posts the best numbers with an extremely small range of values and a tiny 1.36% deviation from 2.2. The U3818DW is only slightly behind with a .23 value range and 1.81% deviation, which represents an average of 2.16.
Color Gamut & Luminance
The U3818DW has hue and saturation controls for all six colors, but we didn’t need to touch them thanks to excellent out-of-box accuracy and a native gamut that nails the sRGB standard.
For details on our color gamut testing and volume calculations, please click here.
On the above CIE charts, any measurement point that at least touches the target square is within 3dE of perfect. As you can see, the Standard mode has no visible errors whatsoever. Luminance levels are nearly all neutral as well.
Custom Color introduces a slight hue error in magenta, but again, it’s not at the visible level. Calibration easily brings that secondary back in line for a final result that’s as good as any professional display we’ve tested. Not only is the native gamut where it should be, accurate gamma means correct saturation and neutral luminance levels throughout the color triangle.
The U3818DW is slightly ahead of its 38” cousins in the color accuracy department thanks to the LG and Acer screens’ over-saturated gamuts. The difference is only visible to our i1 Pro meter, but when deciding between displays at this price point, every detail counts. You can see the bonus color in the volume chart where Dell comes closer to a true 100% sRGB gamut than the top three monitors. With a little bonus red in the mix, we suggest a custom profile when committing any of these products to color-critical work.
MORE: Best Gaming Monitors
MORE: How We Test Monitors
MORE: How To Choose A Monitor
MORE: All Monitor Content