Photo Histogram & Clipping Analyzer

Inspect RGB histograms, clipped channels and tonal percentiles in a photo.

How it works

Upload a photo to measure luminance and RGB distributions, shadow and highlight clipping, and tonal percentiles. Download the full 256-bin analysis and get percentile-based black and white starting points.

Auto-oriented, display-referred 8-bit sRGB analysis. Fully transparent pixels are excluded; other pixels count equally.
Luma is rounded 0.2126 R + 0.7152 G + 0.0722 B. Clipping counts any channel at or below 2, or at or above 253. This does not measure sensor exposure or recover clipped RAW data.
Report 1st, 50th and 99th luminance percentiles using nearest-rank selection. Suggested levels discard 0.5% from each luminance tail; flat or empty images retain 0–255. Values are suggestions, not an exposure judgment.

Sources

RawTherapee: photo development workflow inspiration (RawTherapee)
RawPedia: exposure, levels and tone curves (RawTherapee)

For scripts and AI agents

JSON API: POST https://luminahistogramanalyzer.usefulweb.site/api/v1/calculate (same calculation as this page)
Interface description: OpenAPI 3.1 · AI guide: llms.txt
MCP server (Streamable HTTP): https://luminahistogramanalyzer.usefulweb.site/mcp · tool name lumina_histogram_analyzer

Example request

curl -s -X POST https://luminahistogramanalyzer.usefulweb.site/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{"image":{"filename":"sample.png","contentType":"image/png","contentBase64":"iVBORw0KGgoAAAANSUhEUgAAACAAAAAgAQMAAABJtOi3AAAABlBMVEX/////AADrWueTAAAAEklEQVQI12NgIBb8/09dgjgAAPcnH+GApkH4AAAAAElFTkSuQmCC"}}'