The LG UM6900 is a decent entry-level 4k TV with an IPS panel. Like most IPS TVs, it has a wide viewing angle, but doesn't look as good in a dark room, as it has a low contrast ratio, poor black uniformity, and no local dimming. It has a fast response time and low input lag, great for gaming, but the backlight always flickers, which causes noticeable duplications in motion. Unfortunately, this TV can't get very bright, and it uses a less accurate sub-pixel structure, which isn't ideal for use as a PC monitor.
Note that the 60" and 70" models likely use VA panels, and we expect them to have better contrast and black uniformity, but a worse viewing angle.
Overall, the LG UM6900 is a decent TV for most uses. It's best-suited for watching TV shows, sports, or playing games during the day, and is a good choice for a wide seating area. Unfortunately, it isn't very good for watching movies in a dark room, in SDR, or HDR. It has a great response time and outstanding low input lag, which would make it a great TV for use as a PC monitor, but the RGBW pixel structure isn't as accurate.
This isn't a very good TV for watching movies in a dark room, unfortunately. It has a low contrast ratio, poor black uniformity, and no local dimming feature, so blacks look gray. It can remove judder from 24p sources, but not when watching movies from a cable box.
This is a good TV for watching TV shows during the day, as long as your room isn't too bright. It has great reflection handling and a good viewing angle, great if you like to walk around with the TV on. LG's WebOS has a huge selection of streaming apps, great for cord-cutters. Unfortunately, it can't get very bright, so it isn't a great choice for a really bright room with lots of windows.
Overall, this is a decent TV for watching sports. It has a good viewing angle, great if you have a wide seating area, and it has a fast response time. Unfortunately, it can't get very bright, so it isn't well-suited for a bright room, and there are noticeable duplications in motion from the backlight flicker, which could be distracting when watching sports.
Overall, the LG UM6900 is a great TV for playing video games. It has outstanding low input lag and a great response time, so there is very little blur behind fast-moving objects. Unfortunately, it isn't a great choice for gaming in a dark room, though, and there are noticeable duplications in motion from the flicker of the backlight.
The LG UM6900 is disappointing for watching HDR movies. It has a low contrast ratio, poor black uniformity, and no local dimming feature. It can't get very bright in HDR, and can't display a wide color gamut. It only supports HDR10, and unlike most other LG TVs, it doesn't support Dolby Vision.
This TV has outstanding low input lag and a great response time, so it's great for gaming, but only decent for gaming in HDR. It can't get very bright in HDR, so small highlights don't stand out, and it can't display a wide color gamut.
The design of the LG UM6900 is very basic and feels a bit cheap. It looks very similar to the LG UM7300, but appears to be made of slightly cheaper materials. The stand doesn't support the TV very well as it wobbles a lot, and there is no cable management.
The feet on the LG 49UM6900 are set at opposite ends of the TV, so you'll need a large table for the larger sizes if it isn't VESA mounted. The feet don't support the TV very well, and there's a lot of wobble.
Footprint of the 49" model: 40.7" by 9.2".
The back of the TV is very plain. There is no cable management at all.
The borders are a bit thicker than most higher-end models, so they're a bit more noticeable when watching TV.
The UM6900 is a bit thicker than most higher-end models.
The UM6900 has mediocre build quality. There is a lot of flex in the panels, especially on the back near the inputs, and the stand doesn't support the TV very well, as there is a lot of wobble.
Like most IPS TVs, the UM6900 has a disappointing contrast ratio. This results in blacks that look gray, and is especially noticeable in a dark room.
Note that the 60" and 70" models likely use VA panels, and probably have better contrast.
The LG 49UM6900 doesn't have a local dimming feature. The above video is provided for reference only.
The 49UM6900 has disappointing peak brightness. In a bright room, it can be difficult to see. There is no noticeable variation in brightness with different content, though.
The peak brightness was measured after calibration, with the 'Expert (Dark Room)' Picture Mode. The other picture modes aren't noticeably brighter.
Unfortunately, this TV can't get very bright in HDR. Small highlights in some scenes don't stand out as much as they should. There is also some noticeable variation in brightness with different content.
We measured the HDR peak brightness before calibrating, with the 'Cinema HDR' Picture Mode. The 'Vivid' mode reaches a peak brightness of 383 cd/m², but isn't as accurate.
This TV has decent gray uniformity. There is some noticeable dirty screen effect, which isn't great for watching sports, and the corners are darker than the rest of the screen.
Like most IPS TVs, the UM6900 has a decent viewing angle. This is good if you have a wide seating area, or if you like to move around a bit with the TV on.
Note that the 60" and 70" models likely have VA panels, and probably have a worse viewing angle.
The LG UM6900 has bad black uniformity. There is noticeable clouding throughout the screen, which can be distracting in dark scenes. Unfortunately, there is no local dimming feature to reduce the amount of clouding.
Note that the 60" and 70" models likely have VA panels, so they probably have better black uniformity.
Great reflection handling. Glare can still be an issue in a bright room, though, or if you have light sources opposite the TV.
With our pre-calibration settings, the LG UM6900 has mediocre accuracy. There are noticeable inaccuracies in almost all shades of gray, and some people might notice some inaccuracies in some colors.
After calibration, this TV has much better accuracy. The few remaining inaccuracies aren't noticeable.
You can see our recommended settings here.
720p content, like most cable TV channels, looks great, with no obvious issues.
1080p content, like movies on Blu-ray, looks excellent. There are no obvious issues.
This TV has a decent color gamut, but it can't display a wide color gamut, which is disappointing. The EOTF doesn't follow the PQ curve properly, and almost all scenes are displayed brighter than they should be, including in Game mode. If you find HDR too dim, the 'Vivid' Picture Mode is a bit brighter, as shown in this EOTF.
Unfortunately, the UM6900 has poor color volume. Colors aren't as bright as pure white, and it can't display dark, saturated colors very well due to the low contrast ratio.
This TV has excellent gradient handling. There is some very slight banding, but this shouldn't be noticeable to most people. If you see banding, the Smooth Gradation feature can help, but it can also cause a loss of some fine details.
There are no signs of temporary image retention on the UM6900, even immediately after displaying our static test image for 10 minutes.
Although some IPS panels can suffer from temporary image retention, this doesn't appear to be permanent as the IPS panel in our long-term test appear immune.
The LG 49UM6900 has a great response time. There is some slight overshoot in some transitions, which can be noticeable in dark scenes. The flicker of the backlight causes noticeable duplications in motion, which can be seen in the above photo.
Update 06/17/2020: There was a minor mistake in our BFI scoring. It's been corrected, and the score has increased a bit.
Like most lower-end LG TVs, there is no black frame insertion feature on the UM6900. The backlight always flickers at 120Hz, though, which helps improve the clarity of motion compared to a TV with no flicker.
This TV has an optional motion interpolation feature, which can be used to increase the frame rate of low frame rate content up to 60 frames per second. This can help improve the appearance of motion, but also introduces something known as the "Soap Opera Effect", which may bother some people.
The relatively slow response time of this TV results in less noticeable stutter. Some stutter can still be seen with 24p movies, though, especially in slow, panning shots.
The UM6900 can remove judder from most sources, as long as the Real Cinema setting is enabled. Unfortunately, it can't remove judder from 60p or 60i sources, like a cable box.
This TV has a 60Hz refresh rate, and it doesn't support any advanced variable refresh rate technologies, like AMD's FreeSync.