The uniformity of super wide monitors such as the LG 38UC99 is always a challenge. The lighting is provided by leds on both sides, a special foil should result in a uniform distribution. This is more difficult with very wide monitors. In that light the results of the 38UC99 are not bad at all. The lowest measured value of white compared to the highest has 75% of its brightness, the average deviates 15% from the highest value. With black we see some bigger differences, but the average is not that bad either.
Looking at the measurements in more detail, we primarily notice the upper-middle having a slightly lower black level and higher brightness than the 150 cd/m² at which we have configured the monitor. The bottom right and left both have lower brightness of black and white. With the 15 contrast measurements we see that the deviation is quite low, with 791:1 as worst result and 892:1 as the best – but the latter is an outlier, bottom right. In practice this is definitely not bothersome.
Add to that that the uniformity of the colour temperature is not bad at all, although the results in the middle are warmer than at the edges – a difference of 200K will not easily be noticed with the naked eye. The DeltaE variation compared with the middle stays within reason, with the highest measured value of 3.5 – in theory this should be visible for the trained eye, but a lot of us cannot detect it.
Bear in mind that the colour in the boxes with the uniformity of black, white and the contrast is related to the results of the measurements for that model; not to the absolute values.
- As far as black goes, the lower the measured value, the better (=greener); if the value is higher this means worse (=redder).
- For white the colour coding is different, because there we set a specific brightness of 150 cd/m². That is why values that are closer to this setting green, values that are further away become red – the more they deviate the redder they are.
- As far as contrast is concerned, the highest contrast is green, the lowest is red – the values in between are marked by these colours. Greener is better, redder is worse. We emphasize again that these values are relative: a contrast of 1702:1 is excellent, but if the highest measured contrast is 2581:1, the former value is still marked in red.
- With the colour temperature the measurements are bluer the lower they are, yellower the higher they are.
- Last but not least the colour deviation: here you see a number for the DeltaE value in the boxes, where values below three are barely noticeable with the naked eye. The colour of the boxes shows the colour deviation of gray.