Image MIME Reference
FreeHand
Macromedia FreeHand Document
image/x-freehand
VS
Portable Bitmap
image/x-portable-bitmap
PBM
A complete technical comparison of Macromedia FreeHand Document and Portable Bitmap — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | FreeHand | PBM |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Macromedia FreeHand Document
image/x-freehand
Extension
.fh.fh4.fh5.fh7.fh8.fh9.fh10.fh11.ft11
Container
Proprietary Binary (Aldus Graphic Document)
Compression
Uncompressed / Deflate (in later versions)
Algorithm
NoneDeflate (Optional in later versions)
Color Depth
Vector Data (RGB/CMYK)
Developed by
Altsys / Aldus / Macromedia
Released
1988
Magic Bytes
41 47 44 31 to 41 47 44 34
Portable Bitmap
image/x-portable-bitmap
Extension
.pbm
Container
Netpbm
Compression
Uncompressed
Algorithm
None
Color Depth
1-bit (Monochrome)
Developed by
Jef Poskanzer (Netpbm Project)
Released
1988
Magic Bytes
50 31 (ASCII) or 50 34 (Binary)
Browser Support Comparison
| Browser | FreeHand | PBM |
|---|---|---|
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✕ | ✕ |
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✕ | ✕ |
|
|
✕ | ✕ |
|
|
✕ | ✕ |
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|
✕ | ✕ |
FreeHand
FreeHand Strengths
- Historically one of the most powerful and intuitive vector editors on the market, praised for multi-page support long before Adobe Illustrator implemented it
- Files are generally compact and self-contained
Limitations
- Completely abandoned proprietary format; Adobe actively blocked native import in modern versions of Illustrator
- No support in modern web browsers; must be converted to SVG
- Versioning fragmentation means parsers must account for wildly different binary structures depending on the specific .fhX extension used
PBM
PBM Strengths
- Absolute structural simplicity allows parsers to be written from scratch with just a few lines of code
- ASCII encoding allows manual editing and debugging directly within a standard text editor
- Serves as a flawless, lossless intermediary for 1-bit raster data like scanned documents or barcodes
Limitations
- Strictly limited to 1-bit monochrome images; cannot natively display shades of gray or color
- Lack of compression results in extremely large file sizes, particularly when using the ASCII 'P1' encoding
- No support for alpha transparency or modern metadata standards like EXIF
When to choose which format
FreeHand
Use FreeHand when…
- Legacy Graphic Design Portfolios
- Historical Desktop Publishing Archival
- Old Corporate Logo Vectors
PBM
Use PBM when…
- Optical Character Recognition (OCR) Pre-processing
- Unix/Linux Command-Line Image Pipelines
- Academic Image Processing Teaching