Picture is dark.
If the screen is dim even without adjusting brightness, definition, color, and color density, it may be set as Power Saving Mode or the Picture Mode is set as Eco.
How to fix
① Home button of remote control → Detail Settings → Picture→ Select e Power saving mode from Picture Mode
→ If it is set as Auto Power Saving or Hibernation, select OFF.
② Select Power Saving Mode in the Quick Settings → Deselect Auto Power Saving or Hibernation.
① Adjusting Picture Mode: SMART → SETTINGS → PICTURE → PICTURE MODE→ Standard or Vivid
② Adjusting Power Saving Mode: SMART → SETTINGS → PICTURE → POWER SAVING MODE → Off