How to Convert HDR to PGM

PGM (Portable Graymap) is part of the Netpbm family and stores grayscale image data at 8 bits per pixel, with no color channels at all. It was designed in the late 1980s as a simple, lowest-common-denominator format that's easy for programmers to read and write directly, which is why it's still used as an intermediate format in academic image-processing courses, computer vision research, and command-line Unix tools.

Converting a color HDR file to PGM strips out all color information, leaving only the grayscale luminance values for each pixel once the extended range data has been tone-mapped. This is sometimes used when a luminance map or brightness reference derived from an HDRI image needs to feed into a research tool or computer vision pipeline that expects grayscale data in the PGM format.

1. Install Turbo Batch Image Converter Pro on your Windows PC.
2. Open the app and select Batch Mode for multiple files, or Individual Mode for a single HDR.
3. Drag your HDR file or folder into the app window, enabling recursive folder scanning if needed.
4. Set the "From" format to HDR and the "To" format to PGM.
5. Click Convert. PGM files are written to the output folder, fully offline.

• 100% offline — your HDRI maps and lighting data are never uploaded anywhere
• Produces standard PGM files compatible with Netpbm-based research and processing tools
• Bulk conversion of entire folders, including sub-folders, in one click
• Multi-core processing for fast handling of large batches
• Option to delete original HDR files automatically after conversion
• No recurring subscription or hidden upload limits