HDR to FAX conversion is the process of transforming a High Dynamic Range (HDR) image file—containing extended luminance and color information—into a FAX-compatible image format optimized for fax transmission (monochrome, limited resolution). This conversion typically involves tone mapping and color-to-grayscale rendering plus resizing and compression so the image meets the resolution and binary (black-and-white) requirements of fax machines and fax file standards.
Related guides
Learn More About Image Conversion
Practical guides to help you choose formats, preserve quality, and avoid common conversion problems.
HDR files typically use the image/vnd.radiance MIME type and support various codecs for storing high dynamic range data. FAX files generally utilize the image/fax MIME type and conform to Group 3 or Group 4 fax standards for monochrome image compression. HDR is used primarily in photography and rendering, while FAX is designed for document transmission over telephone lines.
The FAX (.FAX) format is commonly used for image. Understanding its characteristics can be helpful when converting to or from other formats like HDR.
While specific technical details aren't available here, FAX files generally serve the purpose of storing image effectively within their domain.
Convert HDR to FAX Online
Easily convert your HDR files to FAX format online with our fast and secure converter. Designed for users seeking a hassle-free way to transform HDR images into FAX files without software installation or technical knowledge.
Benefits of Converting HDR to FAX
✓Ensure HDR images are formatted to fax standards so documents send reliably over fax lines.
✓Reduce file size dramatically by converting to CCITT-compressed monochrome TIFFs suitable for transmission.
✓Automate batch HDR-to-fax workflows to save time on multi-page or multi-exposure jobs.
✓Retain essential detail with smart tone mapping and dithering before binarization.
✓Create compliant fax files that minimize transmission errors and improve deliverability.
HDR vs FAX Comparison
HDR files store high dynamic range image data with rich color and light information, making them ideal for photography and detailed visuals. FAX files, in contrast, are optimized for monochrome document transmission over phone lines and fax machines, focusing on simplicity and compatibility rather than image quality. This makes converting HDR to FAX suitable for adapting complex images to legacy communication formats.
Supported HDR Input Formats
1HDR input variations:
2- .hdr (Radiance HDR)
3- .exr (OpenEXR, commonly used for HDR image sequences)
4- .pfm (Portable Float Map)
5- HDR images embedded in common containers (e.g., TIFF with HDR channels)
6Input color/profile options:
7- 32-bit float RGB, 16-bit per channel formats, and standard 8-bit HDR-encoded files
8- Embedded color profiles (linear, scene-referred, display-referred)
9FAX output options:
10
Tips & Limits for HDR to FAX Conversion
Keep input HDR images under 250 MB for smooth web-based conversions; very large HDR exposures or EXR stacks may require local preprocessing before conversion.
Preserve important detail by applying tone mapping and contrast adjustment prior to binarization; choose adaptive thresholding and dithering to retain texture when converting to monochrome.
For multi-page faxes or bulk jobs, batch-convert HDR frames to monochrome TIFF with CCITT Group 4 compression to reduce file size while maintaining fax compatibility.
Limitations: fax formats are strictly monochrome with low dynamic range—color, HDR luminance, and fine grayscale nuances will be lost during conversion.
Frequently Asked Questions
What is the best way to convert HDR to FAX?▼
The best approach is to first tone-map the HDR image to normalize luminance and preserve visible detail, then convert to grayscale and apply adaptive thresholding or dithering before encoding as a CCITT Group 3 or Group 4 TIFF. This workflow maintains legibility and minimizes artifacts when the image is transmitted via fax.
Is HDR to FAX conversion free?▼
Yes, ConvertFiles offers free HDR to FAX conversion for basic usage, typically with limits on file size and batch volume. Paid or premium plans may remove those limits and provide faster processing or higher maximum file sizes.
Will I lose quality converting HDR to FAX?▼
Yes—fax formats are strictly monochrome and low dynamic range, so you will lose color and much of the HDR luminance information; however, proper tone mapping, adaptive thresholding, and dithering can preserve the important details and legibility. The end result is optimized for clarity on fax machines rather than photographic fidelity.
How long does HDR to FAX conversion take?▼
Conversion time depends on file size, complexity (multi-channel EXR stacks take longer), and server load, but single images typically process in seconds to a minute on a modern web service. Batch jobs or very large HDR files may take several minutes.
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- Standard fax-ready bitonal images (G3 1-D/2-D compression like TIFF-FX / TIFF-F or .tiff with CCITT Group 3/4)
11- Black-and-white TIFF (.tiff) with CCITT Group 3 or Group 4 compression
12- Single-page monochrome PNG or BMP optimized for fax compatibility (binary dithered)
13Conversion settings and compression options:
14- Tone mapping method: Reinhard, exposure/contrast adjustments
15- Dithering: Floyd–Steinberg or ordered to preserve detail after binarization
16- Resolution/scale: common fax widths (e.g., 203 x N dpi or 200/204 dpi) and A4/Letter page sizing
17- Compression: CCITT Group 3 (MH), Group 4 (MR) options and adjustable line density/bitrate
18Quality and processing settings:
19- Contrast/brightness overrides, gamma correction, and sharpening before binarization
20- Selectable thresholding (global vs. adaptive) for black-and-white conversion
If you need better visual fidelity in the recipient’s copy, resize to the target fax resolution (typically ~200 dpi width) and preview the dithered output before sending.
Can I convert multiple HDR files to FAX at once?▼
Yes, batch conversion is supported; you can queue multiple HDR files and output them as individual fax-ready TIFFs or merge pages into a single multi-page TIFF. For large batches, use compression (Group 4) and consistent sizing to speed processing and minimize output size.
What is the maximum file size for HDR to FAX conversion?▼
Free users can convert files up to 250MB, premium users up to 1GB, though extremely large HDR stacks may still require local preprocessing for reliability. If your file exceeds limits, split exposures or flatten layers before uploading.
Is my HDR file secure during conversion?▼
Yes, conversions are handled over encrypted connections (HTTPS) and temporary files are deleted after processing according to standard privacy policies. For sensitive material, consider using a local tool or a paid account with documented retention and security guarantees.
