Dark and washed-out are two different faults and they don't share a fix. Dark is the picture preset and the panel's output ceiling. Washed-out is usually the signal arriving wrong, which is a port or a source problem. Sort out which one you have before changing anything, because the settings that fix one make the other worse.
And before anything else: on almost every TV, the slider labelled "Brightness" is black level, not output. Raising it to fix a dark picture lifts the blacks to grey and flattens the image, which is how a dark picture becomes a washed-out one. The control you actually want is OLED Light on LG, Backlight on most LCD sets, or Brightness on Samsung — Samsung being the confusing exception that uses the word for output.
If HDR looks too dark
- Use an HDR preset, not an SDR one. HDR has its own set — HDR Cinema, Filmmaker, or HDR Standard. Filmmaker is the accurate one and looks dim in a lit room; Cinema or Standard is the better daytime choice and no less "correct" if the room is bright.
- Raise OLED Light or Backlight. HDR presets ship this low. This is the master output control and the one that actually makes the picture brighter.
- Turn off the ambient dimmer. Energy Saving, Eco Mode, or Ambient Light Sensor will quietly pull brightness down and fight every change you make. Turn it off first or you'll be adjusting against a moving target.
- Leave the eco setting off after a firmware update. Several manufacturers re-enable energy saving on update. If a picture you calibrated months ago has gone dim on its own, check this before anything else.
If the picture looks washed out or flat
- Confirm it's actually receiving HDR. Grey, low-contrast images often mean the TV is displaying SDR while the source thinks it's sending HDR. Most sets show an HDR or Dolby Vision badge briefly on input change, or report the format in an info panel.
- Turn on the input's enhanced HDMI mode. LG Deep Color, Samsung Input Signal Plus, Sony Enhanced format. Without it the port runs reduced chroma and everything looks desaturated. It is per-input, so enabling it on HDMI 2 does nothing for the box on HDMI 3.
- Put Color and Contrast back to default before nudging. A lowered Contrast flattens HDR highlights, and it's a common leftover from someone trying to fix glare.
- Rule out the cable. A marginal cable drops HDR metadata rather than failing outright, and dropped metadata renders as flat colour across everything — a certified Ultra High Speed cable settles it.
If an Apple TV is the source
The Apple TV causes more wrong-looking HDR than any TV setting, and it's one option.
The box can either force one fixed format on everything or match each title's native format. Forcing Dolby Vision is the single most common cause of dim, oddly-tinted HDR, because the TV then applies Dolby Vision tone-mapping to SDR and HDR10 content that was never graded for it.
Turn on Settings > Video and Audio > Match Content > Match Dynamic Range, and Match Frame Rate while you're there. SDR then stays SDR, HDR10 stays HDR10, and Dolby Vision only engages on actual Dolby Vision material.
Set Format to 4K SDR as your base and let Match Dynamic Range do the switching. Choose 4K Dolby Vision as the base only if you know your set handles DV well — on several TVs the Dolby Vision preset is noticeably dimmer than HDR10, and on those, forcing DV is exactly what's making your picture dark.
Then run Check HDMI Connection in the same menu. It takes two minutes, blanks the screen partway through, and tells you what the chain actually negotiated rather than what you asked for.
For a colour cast rather than a brightness problem, Settings > Video and Audio > Calibration > Color Balance uses an iPhone's front-facing camera and light sensor to read the screen and correct white balance. It fixes tint. It won't fix dim.
HGiG, and when it's the wrong answer
If your set has an HDR Tone Mapping option listing HGiG alongside Dynamic or Active, it's worth knowing what you're choosing.
HGiG — the HDR Gaming Interest Group, an industry body including Sony, Microsoft, LG, Panasonic and Samsung — is not a picture enhancement. Selecting it tells the TV to stop tone mapping entirely and let the console do it. It exists to prevent double tone mapping, where the console maps HDR to what it thinks your panel can do and the TV then maps that result again.
Which means HGiG only helps after you have run the console's own HDR calibration screens. Switch it on without doing that and the console is guessing at your panel's capability while the TV has stopped compensating — usually darker and more crushed than leaving Dynamic on.
For film and streaming, Dynamic or Active tone mapping is generally the better choice, particularly on sets with strong peak brightness. There's no universally correct setting here; there is a correct setting for what you're watching.
If it's blown out instead
Lower Contrast or Backlight slightly, turn off Dynamic Contrast — it clips highlight detail to look punchier — and move off Vivid to Cinema or Filmmaker. Vivid exists to win arguments in shop lighting and it clips everything.
See also
FAQ
Why is HDR so dark? The HDR preset ships dim and the ambient dimmer pulls it lower. Pick HDR Cinema or Filmmaker, raise OLED Light or Backlight, and turn off Energy Saving.
Which slider is brightness? OLED Light on LG, Backlight on most LCDs. The slider named "Brightness" is black level on nearly every brand except Samsung, where it is output.
HDR looks flat and grey. Either the set isn't actually in HDR, the input's enhanced HDMI mode is off, or the cable is dropping metadata. Check in that order.
My Apple TV HDR looks dim and slightly off-colour. It's forcing Dolby Vision on everything. Turn on Match Dynamic Range and set the base format to 4K SDR.
Should I use HGiG? Only for console gaming, and only after running the console's HDR calibration. Otherwise leave tone mapping on Dynamic.