How to convert HDR to PGM
To convert HDR to PGM, upload your HDR file, choose PGM as the output format and press Convert. The finished PGM 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 HDR images into PGM 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.
Reasons to switch from HDR to PGM
- Simple grayscale storage
- Easy to parse
- Good for algorithms and teaching
- Works with: GIMP, ImageMagick, Netpbm, OpenCV and MATLAB
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 holds values brighter than a normal screen can show, so the image is clipped to the displayable range and converted to sRGB. Very bright highlights lose their extra range.
- PGM stores only brightness, so the colour image is converted to grayscale.
- Browsers do not display PGM files, so use it in editors, print workflows or development tools rather than on a web page.
HDR vs PGM
| Property | HDR | PGM |
|---|---|---|
| Full name | Radiance RGBE | Portable Graymap |
| Released | 1989, Greg Ward (Radiance) | 1988, Jef Poskanzer (Netpbm) |
| Compression | None (uncompressed) | None (uncompressed) |
| Transparency | No | No |
| Animation | No | No |
| Bit depth | 32-bit shared exponent | 8 or 16-bit gray |
| Shown in browsers | No | No |
| Best for | 3D lighting and HDRI skies; image-based lighting | grayscale processing; image-analysis research |
Steps to convert HDR to PGM
- Drop your HDR image file onto the converter, or click to choose it.
- Check that PGM is selected as the target and adjust the options if you want.
- Press Convert, then download your new PGM 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 HDR to PGM?
Drop your HDR files on the converter, confirm that PGM is the target and press Convert. Download each file or the whole batch as a ZIP.
Is the HDR to PGM 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 HDR to PGM 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 HDR to PGM?
HDR images do not contain transparency, so there is nothing to lose. PGM does not support it either.
Which programs open PGM files?
PGM files open in GIMP, ImageMagick, Netpbm, OpenCV and MATLAB.
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.