How to convert PNM to HDR
To convert PNM to HDR, upload your PNM file, choose HDR as the output format and press Convert. The finished HDR file is ready to save to your phone or computer in seconds, free, with no watermark and no sign-up. Your file is deleted from our server about 30 minutes after the conversion.
This free online converter changes PNM images into HDR files in seconds, with no software to install and no watermark. You can convert several files at once, resize them and choose the quality for formats that support it. Metadata such as location tags is removed from the output for privacy.
Why convert PNM to HDR?
- High dynamic range in a compact encoding
- Standard for environment maps
- Simple format
- Works with: Blender, Photoshop, Unity, Unreal and Radiance tools
What to expect from this conversion
- Both formats store the pixels without loss, so the picture stays identical. Only the file size and compatibility change.
- HDR stores light in linear floating-point values, so your pixels are converted from sRGB to linear. The result looks the same in an HDR-aware viewer but does not gain real dynamic range.
- Browsers do not display HDR files, so use it in editors, print workflows or development tools rather than on a web page.
PNM vs HDR
| Property | PNM | HDR |
|---|---|---|
| Full name | Portable Anymap | Radiance RGBE |
| Released | 1988, Jef Poskanzer (Netpbm) | 1989, Greg Ward (Radiance) |
| Compression | None (uncompressed) | None (uncompressed) |
| Transparency | No | No |
| Animation | No | No |
| Bit depth | 1, 8 or 16-bit | 32-bit shared exponent |
| Shown in browsers | No | No |
| Best for | Unix-style image pipelines; teaching and research | 3D lighting and HDRI skies; image-based lighting |
Steps to convert PNM to HDR
- Drop your PNM image file onto the converter, or click to choose it.
- Check that HDR is selected as the target and adjust the options if you want.
- Press Convert, then download your new HDR file when it finishes.
Tips for the best result
- Use quality 80 to 90 for photos: it is visually close to the original at a much smaller size.
- Set a width if the image will be shown on a small screen, which also reduces the file size.
- Choose a background colour before converting transparent images to a format without transparency.
Frequently asked questions
How do I convert PNM to HDR?
Drop your PNM files on the converter, confirm that HDR is the target and press Convert. Download each file or the whole batch as a ZIP.
Is the PNM to HDR converter free?
Yes. It is free with no watermark, no sign-up and no limit on how many images you convert. The site is supported by ads.
Does converting PNM to HDR reduce quality?
Both formats store the pixels without loss, so the picture stays identical. Only the file size and compatibility change. The quality slider only affects formats that use lossy compression.
Will transparency be kept when I convert PNM to HDR?
PNM images do not contain transparency, so there is nothing to lose. HDR does not support it either.
Which programs open HDR files?
HDR files open in Blender, Photoshop, Unity, Unreal and Radiance tools.
How many images can I convert at once?
Up to 20 images per batch, each up to 60 MB. Files are deleted from the server about 30 minutes after conversion.