Brighter than white
Gainmaps
The original, gain map encoded. Standard reads the SDR base. Ultra lifts the highlights.
Photo by Maarten Zaanen on Unsplash · Original
Type
Ultra
Ultra
Same text, same display — left is SDR white, right is Ultra.
Convert your image
Drop any photo or logo. We add a gain map layer and return it to you instantly — same file format, no upload, no account, no registration. Completely private, runs in your browser.
INSTANT IN BROWSER
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What is a gain map image?
HDR is an expanded brightness range: image highlights can sit above the SDR ceiling. A gain map image encodes a normal SDR image plus a secondary brightness map. Unsupported apps render the SDR layer and ignore the rest.
EDR is Apple's term for displaying brightness above SDR reference white. HDR describes the image content. They are not the same word and are often misused interchangeably.
The cross-platform technical name is HDR gain map image. Consumer brands include Adaptive HDR (Apple) and Ultra HDR (Android/Google). This site encodes those files locally in the browser. No upload, no server.
Blacks do not necessarily get blacker. EDR lifts highlights, not the shadow floor.
For developers
Build gain map encoding into your pipeline or CI. MIT licensed, 100% test coverage, available via Docker, npm, Homebrew, and curl.
DockernpmHomebrewcurlCLIMIT licensed100% test coverage
Add Ultra text to your project
Learn more →npx skills add kirkstrobeck/gainmapsThe skill is the recommended path because this rendering stack has edge-treatment details that can be updated without retyping the implementation by hand. View skill source on GitHub →