Limited Range vs Full Range: What Actually Happens
A digital RGB pixel has 256 possible values per channel (0-255). "Full range" uses all of them. "Limited range" (also called Video range, TV range, or 16-235) reserves 0-15 for blacker-than-black and 236-255 for whiter-than-white, leaving only 16-235 for actual image data. TVs and Blu-rays use limited range because old analog broadcast standards did. PCs use full range because software assumes every pixel value is meaningful.
When PC content is displayed in limited range, values 0-15 all clip to pure black and 236-255 all clip to pure white. Near-black and near-white details vanish.
Why This Happens Over HDMI
HDMI was designed for TVs, so the handshake often defaults to limited range, even between a PC and a PC monitor. Windows and the graphics driver will comply without warning. The symptoms are always the same: black shadows that should have detail look flat pitch-black; white highlights blow out. Gamers notice it first in dark scenes where they can't see enemies in shadow.
What This Test Shows
Two rows of 32 patches each. The first row steps from RGB 0 to RGB 31 — the near-black range. On a correctly configured full-range display, all 32 patches are visually distinguishable: darker on the left, gradually lighter. On a limited-range setup, the first 16 patches (RGB 0-15) all clip to pure black and look identical. The second row does the same at the highlight end (RGB 224-255) — limited range crushes the last ~20 patches into pure white.
Fixing The Range
On the GPU side: NVIDIA Control Panel → Resolution → "Output dynamic range: Full", or AMD Radeon Software → Display → "Color Range: Full". On the TV / monitor side: look for "HDMI Black Level" (Sony), "Input Level" (LG), "RGB Range" (Samsung), or "Black Level" (Xbox Series / PS5) and set to Full / Normal / PC. Mismatches cause crushed blacks OR washed-out whites depending on which side is wrong.
