Image MIME Reference
NAPLPS
North American Presentation Level Protocol Syntax
image/naplps
VS
Radiance HDR
image/vnd.radiance
Radiance
A complete technical comparison of North American Presentation Level Protocol Syntax and Radiance HDR — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | NAPLPS | Radiance |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | Yes | ✕ No |
| Progressive Loading | Yes | ✕ No |
| HDR Support | ✕ No | Yes |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
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)
Radiance HDR
image/vnd.radiance
Extension
.hdr.pic.rgbe.xyze
Container
Radiance Information Header
Compression
Run-Length Encoding (RLE) / Uncompressed
Algorithm
Adaptive Run-Length Encoding (RLE)
Color Depth
32-bit (8-bit per channel RGB + 8-bit shared Exponent)
Developed by
Greg Ward (Lawrence Berkeley National Laboratory)
Released
1989
Magic Bytes
23 3F 52 41 44 49 41 4E 43 45
Browser Support Comparison
| Browser | NAPLPS | Radiance |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
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
Radiance
Radiance Strengths
- Universally supported by almost every 3D modeling software, renderer, and game engine in existence
- RGBE encoding offers a brilliant balance between High Dynamic Range capability and small file size (compared to 32-bit float OpenEXR)
- Simple, easy-to-parse ASCII header followed by straightforward RLE binary data
Limitations
- Does not support alpha transparency (no way to store an isolated light source with a transparent background)
- The shared exponent architecture can occasionally introduce banding or color artifacts in extreme edge cases compared to true 16-bit/32-bit floating-point formats like OpenEXR
- Zero native browser support for 2D viewing
When to choose which format
NAPLPS
Use NAPLPS when…
- 1980s Videotex Services
- Prodigy Online Service Graphics
- Historical BBS Terminal Graphics
- Legacy Teletext Broadcasts
Radiance
Use Radiance when…
- Image-Based Lighting (IBL)
- 3D Environment Maps (HDRI Skydomes)
- Lighting Simulation
- VFX and CGI Rendering