Image MIME Reference
DNG
Adobe Digital Negative
image/x-adobe-dng
VS
North American Presentation Level Protocol Syntax
image/naplps
NAPLPS
A complete technical comparison of Adobe Digital Negative and North American Presentation Level Protocol Syntax — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | DNG | NAPLPS |
|---|---|---|
| Transparency (Alpha) | Yes | ✕ No |
| Animation Support | ✕ No | Yes |
| Progressive Loading | ✕ No | Yes |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Adobe Digital Negative
image/x-adobe-dng
Extension
.dng
Container
TIFF/EP
Compression
Lossless JPEG / Deflate / Lossy JPEG (DNG 1.4+)
Algorithm
Lossless JPEG (Standard)Lossy JPEG (Compression option)Uncompressed
Color Depth
12-bit, 14-bit, 16-bit, 32-bit (Floating Point HDR)
Developed by
Adobe Systems
Released
2004
Magic Bytes
49 49 2A 00 or 4D 4D 00 2A
North American Presentation Level Protocol Syntax
image/naplps
Extension
.nap.naplps
Container
NAPLPS Byte Stream
Compression
Uncompressed (Tokenized ASCII Commands)
Algorithm
None (Coordinate encoding)
Color Depth
16-color palette (Indexed from larger color spaces)
Developed by
ANSI / CSA (Based on Canadian CRC's Telidon)
Released
1983
Magic Bytes
1B (Variable / ESC sequences)
Browser Support Comparison
| Browser | DNG | NAPLPS |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
DNG
DNG Strengths
- Openly documented specification guarantees long-term archival accessibility, freeing photographers from proprietary manufacturer lock-in
- Lossless compression algorithms often result in files 15-20% smaller than uncompressed proprietary raw formats
- Natively supported by modern smartphone operating systems (iOS and Android) for high-end mobile photography
Limitations
- Conversion from proprietary raw to DNG takes processing time and can strip specific, proprietary manufacturer metadata (like active D-Lighting or in-camera lens corrections)
- File sizes are massive compared to standard JPEGs or HEIC files
- Cannot be rendered natively in web browsers without server-side processing or WebAssembly decoders
NAPLPS
NAPLPS Strengths
- Extremely bandwidth-efficient, enabling colorful graphical interfaces over early 300 baud dial-up connections
- Resolution-independent vector scaling allowed the exact same file to be displayed accurately on varied early PC monitors and television sets
Limitations
- Completely obsolete and unsupported by modern web technologies
- Relies heavily on stateful parsing and terminal emulators rather than straightforward file decoding
- Easily misidentified by MIME sniffers as plain text or generic binary streams due to the lack of a standardized file header
When to choose which format
DNG
Use DNG when…
- Digital Photography Archival
- Mobile Raw Capture (iOS ProRAW / Android Camera2 API)
- Cross-Platform Raw Editing Workflows
NAPLPS
Use NAPLPS when…
- 1980s Videotex Services
- Prodigy Online Service Graphics
- Historical BBS Terminal Graphics
- Legacy Teletext Broadcasts