File failed QC: Luma High Gamut Failure or Luma Low Gamut Failure

If your QC report shows Luma High Gamut Failure or Luma Low Gamut Failure in red, parts of your picture are too bright or too dark for broadcast.

Luma – reading the QC report

• Luma High Gamut Failure means parts of the picture are brighter than broadcast allows.
• Luma Low Gamut Failure means parts of the picture are darker than broadcast allows.
• Luma Max Peak and Luma Minimum show the brightest and darkest levels in your file.

Luma – what it means

Luma (luminance) is the brightness of the picture. Broadcast video must stay within a "legal" brightness range. Anything brighter or darker than that range can be clipped or distorted on TV. The QC measures luma to the EBU R103 standard: video levels 16–235 (not the full RGB 0–255 range).

Luma – likely cause

This is usually a file fault. Common causes:

• The grade has very bright highlights (super-whites) or very dark blacks that go beyond the legal range.
• Graphics, titles or packshots use pure white or pure black from an RGB source.
• The file was exported using full range (0–255) instead of video (legal) range.

Luma – fix

1. Apply a broadcast-safe or legaliser filter (sometimes called a video limiter) to the timeline or on export, so brightness stays within the legal range.
2. Re-export the file using the matching Export Guide.
3. Upload the file again.

Luma – when to contact Customer Success

• You’ve exported the file using the specification shown by the View Specs link for the ad in your campaign, but it still fails this check.