If your LG CX shows a picture that is too dark, with a dim screen in daylight, crushed shadows or flat HDR, the cause lies in the settings, in the way an OLED limits brightness or, occasionally, in the age of the panel, and a few steps usually restore a good picture. The CX is a 2020 OLED with the Alpha 9 Gen3 processor and an older webOS. It is self-emissive, with each pixel making its own light, so it cannot match the peak brightness of a bright LCD in a sunny room, and it limits its total light output with an Auto Brightness Limiter when a large area is very bright. Settings and modes can also darken the picture a great deal.
The checks in more detail
Start with the picture mode. Press the settings button, open Picture, Picture Mode Settings, and choose a mode such as Standard, Cinema or Vivid for a brighter picture; the Filmmaker mode and Cinema Home are meant to be dim and accurate for a dark room. Raise OLED Pixel Brightness, which is the main brightness control on an OLED, and Contrast. Turn off Energy Saving, in General, Eco, and Automatic Brightness, which dims the picture as the room darkens or the content changes. Check Dynamic Tone Mapping and Dynamic Contrast, which can brighten dark scenes, and the Black Level, which should match the source's range, Auto or Low and High as needed. Then the source and HDR.
Make sure the HDMI input is set to its enhanced or Deep Color mode for 4K HDR, and that the device's output is set to HDR. HDR content is mastered for a dark room, so it can look dark in a bright room; in a bright room, use the HDR picture modes with Dynamic Tone Mapping, or the Vivid mode, and close the curtains. A dimmer picture in a bright room is an OLED trait. Keep the screen clean, and reduce reflections. Watch for a one-off dimming when a bright white screen fills the display, which is the brightness limiter.
If the screen is dim on every source in a dark room with all the settings correct, contact LG with the model number, since an aging OLED panel may need service.
Age is part of this story. A 2020 panel has had years of use, and an OLED that has run bright for thousands of hours may be dimmer than when it was new, especially in the blue sub-pixels that wear fastest. The TV runs a compensation routine that you can start from the support menu, and LG advises leaving the TV in standby, plugged in, so that it can finish its automatic pixel refresh. If the dimming appears as a patch, a permanent image or uneven brightness, take a photograph and compare it with the settings; a mark that remains after a refresh is wear, which only a panel replacement fixes. An older webOS also lacks the newer picture options, so update to the latest software.
Differential
Likely causes of “LG CX OLED TV picture is too dark or keeps dimming”, and how to tell them apart
- 1
A dim picture mode
What separates it The picture is dark in all content
How to confirm Choose Standard, Cinema or Vivid and raise OLED Pixel Brightness
- 2
Energy Saving or auto brightness
What separates it The brightness changes with the room
How to confirm Turn them off
- 3
HDR in a bright room
What separates it The picture is dull
How to confirm Use an HDR mode with Dynamic Tone Mapping
- 4
The brightness limiter
What separates it A large bright area dims
How to confirm It is normal on an OLED
- 5
An aging panel
What separates it Dim on every source in the dark
How to confirm Contact LG
Before you touch a setting
Record this first — changing settings destroys the evidence
- The picture mode and brightness
- Whether energy saving is on
- Which content looks dark
- The room's lighting
Try in this order
0 of 6 completedChoose a brighter mode
ReversibleStandard or Vivid.
Raise OLED Pixel Brightness
ReversibleAnd contrast.
Turn off Energy Saving
ReversibleAnd auto brightness.
Check HDR settings
ReversibleInput and device.
Reduce room light
ReversibleOr reflections.
Contact LG
ReversibleIf dim in the dark.
Model-specific
What is true of this model and not of its siblings
- OLED brightness
- The control is OLED Pixel Brightness.
- Limiter
- A large bright area is dimmed.
- Modes
- Filmmaker is dim by design.
- Energy saving
- It lowers brightness.
- HDR
- It is mastered for a dark room.
- LG help
- Quote the model number.
- Panel age
- Years of bright use can dim an OLED slightly.
- Pixel refresh
- Leave the TV in standby so it can run.
Stop boundary
When this stops being a self-service repair
- !Avoid leaving one still picture on the panel for many hours
- !Do not open the TV
- !Phone LG if a dark room still looks dim on every input
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Why is my LG CX too dark?+
A mode, energy saving or the brightness limiter.
Is an OLED dimmer than an LCD?+
In a bright room, yes.
What is OLED Pixel Brightness?+
The main brightness control.
Does HDR look dark?+
In a bright room, it can.
Is it a defect?+
Rarely.
Does an OLED get dimmer with age?+
Slowly, and the TV runs automatic compensation to even it out.
What is the pixel refresh?+
A routine that evens wear; leave the TV in standby to let it run.