Dynapik offers a free online tool to change image types - no need to download anything. It's quick and easy to use. You can change your HDR images to ICO format. This tool works for both professionals and casual users. Convert your images to ICO in seconds.
Radiance HDR
The pioneering high dynamic range format for lighting simulation.
The Radiance HDR format (often called RGBE) is a raster image format designed for storing high dynamic range (HDR) data. Rather than standard 8-bit integers, it uses a specialized encoding where pixel colors are stored as Red, Green, and Blue mantissas sharing a single common Exponent (RGBE). This allows it to represent a vast range of luminance values, from direct sunlight to deep shadows, in a relatively compact 32-bit-per-pixel format.
The .hdr format consists of a human-readable header containing variables like exposure and gamma, followed by binary pixel data. The pixel data typically uses the 'Radiance RGBE' encoding. Each pixel is 4 bytes: one byte each for Red, Green, and Blue, and one shared Exponent byte. This 'shared exponent' scheme is efficient but introduces some limitations—if one channel is very bright and another is very dark in the same pixel, color precision can be lost (color banding).
Developed by Greg Ward in the late 1980s for the Radiance lighting simulation system. It was one of the first formats to enable practical HDR storage and became a de facto standard in the CGI industry for Image-Based Lighting (IBL).
Microsoft Icon
The standard format for icons on Microsoft Windows and the web (favicons).
The ICO format is a container for one or more images at multiple sizes and color depths. It allows a single file to store appropriate icons for different display contexts (e.g., 16x16 for menus, 256x256 for desktop). It supports transparency and, in modern versions, PNG compression.
ICO files contain a header followed by an icon directory that lists each image entry. Each entry can use either BMP (uncompressed) or PNG compression. The format supports 1, 4, 8, 16, 24, and 32-bit color depths with optional alpha channels.
Introduced with Microsoft Windows 1.0. It became the standard for website favicons with the release of Internet Explorer 5.
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