What Is an HDR File?

You can open and convert an HDR image with Photoshop

What to Know

  • An HDR file is a high dynamic range image file.
  • Open one with Photoshop or Photomatix.
  • Convert to JPG and other image formats with those same programs.

This article explains what an HDR file is (there are two kinds), how to open one on your computer, and how to save one to a different image format.

What Is an HDR File?

A file with the HDR file extension is a high dynamic range image file. Images of this type aren't generally distributed, but instead edited and then saved to a different image format, like TIFF.

HDR files used in Photoshop
HDR files used in Photoshop.

Geographic Information System (GIS) files that contain information on the format and layout of an ESRI BIL file (.BIL) are called ESRI BIL header files, and also use the HDR file extension. They store information in the ASCII text format.

HDR is also short for a number of terms that are unrelated to a file format, like high data rate, hard disk recorder, and high data duplicator.

How to Open an HDR File

HDR files can be opened with Adobe Photoshop, ACD Systems Canvas, HDRSoft Photomatix, and probably some other popular photo and graphics tools as well.

You might also have luck with the online viewer at OpenHDR.org if you want to open it online, or Image Convert Ninja.

If your file isn't an image but instead an ESRI BIL header file, you can open it with ArcGIS, GDAL, or Global Mapper.

If you find that an application on your PC does try to open the file, but it's the wrong application or you'd rather have another installed program open it, see How to Change File Associations in Windows to learn how to make a particular program launch when the file is opened.

How to Convert an HDR File

Imagenator is one free file converter that can convert an HDR file. It supports batch conversions between several image formats, including HDR, EXR, TGA, JPG, ICO, GIF, and PNG. Another good online option is Convertio.

You can also open one in one of the programs from above and then save it to a different image file format. Photoshop can save an HDR file to PSD, EXR, RAW, TIFF, PBM, and other image formats.

Photoshop converting an HDR file
Photoshop's HDR conversion options.

If an ESRI BIL header files can be converted at all, it's most likely accomplished through one of the programs linked above. Typically, the option for converting a file in a program like one of those is available through the File > Save As menu or some type of Export option.

If you need to convert HDR to cubemap, CubeMapGen may be what you need.

Still Can't Open the File?

If your file isn't opening with any of the programs described above, you could be misreading the file extension, mistaking another file format for this one. If this happens, you'll probably receive an error when trying to use the file with an HDR-compatible program.

Some examples of file extensions that closely resemble this one and that could be easily confused for it, include HDS (Parallels Desktop Hard Disk), HDP (HD Photo), and HDF (Hierarchical Data Format).

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