Grayscale output
Colour is converted to grayscale using linear-sRGB luminance and the sRGB transfer curve. Colour channels and transparency are not retained.
Convert HDR to PGM
- In your browser
- No upload
- Private by design
What happens when you convert HDR to PGM?
HDR to SDR
HDR is rendered to SDR using exposure and Reinhard tone mapping.
Lossless sample storage
Netpbm stores these samples without compression. Reducing colour, thresholding or changing maxval can still lose information before storage; text and binary representations change the layout, not its image meaning. PGM can store its supported image samples without lossy compression. This applies after rendering and sample conversion: it does not guarantee preservation of source precision, colour space or document structure, and cannot undo earlier losses.
HDR
Source
HDR
Radiance HDR / RGBE
Compression: LosslessTransparency: NoMetadata: Radiance header, EXPOSURE, FORMAT
Radiance pictures with a shared exponent for high-dynamic-range lighting values.
Explore HDR format →PGM
Target
PGM
Portable Graymap
Compression: UncompressedTransparency: NoMetadata: Header, Comments
Portable Graymap: simple uncompressed raster samples for image-processing pipelines.
Explore PGM format →Is HDR → PGM right for you?
Good choice when
- PGM fits your delivery use: Grayscale images & masks.
- Your processing pipeline explicitly needs grayscale samples.
- You need an SDR delivery copy and can review its tone mapping.
- You need lossless storage of the rendered samples supported by PGM.
Probably not when
- Colour distinctions carry information you need to retain.
- You need the original HDR range for relighting or grading.
- You expect lossless encoding to restore lost details or editing structure.
- You require identical samples without a defined colour and precision policy.
HDR to PGM conversion details
- Grayscale output
- Colour is converted to grayscale using linear-sRGB luminance and the sRGB transfer curve. Colour channels and transparency are not retained.
- HDR to SDR
- HDR is rendered to SDR using exposure and Reinhard tone mapping.
- Lossless sample storage
- Netpbm stores these samples without compression. Reducing colour, thresholding or changing maxval can still lose information before storage; text and binary representations change the layout, not its image meaning. PGM can store its supported image samples without lossy compression. This applies after rendering and sample conversion: it does not guarantee preservation of source precision, colour space or document structure, and cannot undo earlier losses.
- Sample precision & colour
- Pixel conversion only. Original EXIF, GPS, XMP and ICC profiles are not copied; processing uses 8-bit display pixels.
- Metadata & colour
- Pixel conversion only. Original EXIF, GPS, XMP and ICC profiles are not copied; processing uses 8-bit display pixels.
- Compression
- HDR: Lossless → PGM: Uncompressed HDR: RLE preserves stored RGBE bytes; RGBE quantization is not exact storage of arbitrary float RGB. The .hdr format is distinct from the general concept of HDR photography. PGM: Netpbm stores these samples without compression. Reducing colour, thresholding or changing maxval can still lose information before storage; text and binary representations change the layout, not its image meaning.
- Colour depth
- HDR: 32-bit RGBE / XYZE pixel → PGM: maxval up to 65535
- HDR
- HDR: Radiometric values
- Dimensions
- Rendered image dimensions are retained within the converter limits; this tool does not offer resizing. Orientation handling depends on the source decoder.
- Metadata
- Pixel conversion only. Original EXIF, GPS, XMP and ICC profiles are not copied; processing uses 8-bit display pixels.
Common questions
Will PGM keep the source colours?
Colour is converted to grayscale using linear-sRGB luminance and the sRGB transfer curve. Colour channels and transparency are not retained.
How will HDR brightness be mapped?
HDR is rendered to SDR using exposure and Reinhard tone mapping.
Does lossless output mean an unchanged source?
Netpbm stores these samples without compression. Reducing colour, thresholding or changing maxval can still lose information before storage; text and binary representations change the layout, not its image meaning. PGM can store its supported image samples without lossy compression. This applies after rendering and sample conversion: it does not guarantee preservation of source precision, colour space or document structure, and cannot undo earlier losses.
Are bit depth and colour values guaranteed to match?
Pixel conversion only. Original EXIF, GPS, XMP and ICC profiles are not copied; processing uses 8-bit display pixels.
Will metadata and colour profiles be retained?
Pixel conversion only. Original EXIF, GPS, XMP and ICC profiles are not copied; processing uses 8-bit display pixels.