RAS File Format (.ras)
A RAS file is a Sun Raster bitmap, the raw framebuffer image format Sun Microsystems built into SunOS workstations, and it is byte-for-byte identical to the format most tools also recognise under the .sun extension.
RAS at a glance#
| Full name | SUN Rasterfile |
|---|---|
| File extension | .ras |
| Category | Image Files |
| Developer | Sun Microsystems |
| MIME types | image/x-sun-raster |
| Other extensions | .sun |
| Compression | Varies from file to file |
| FileFlip support | FileFlip reads and writes this format |
Strengths and limitations of RAS#
What RAS does well
- Simple enough to decode with just a 32-byte header and a loop over the pixel data
- Palette-based files stay compact even without any algorithm-level compression
- One decoder handles both the .ras and .sun extensions, since the files are identical
Where RAS falls short
- Tied to SunOS and Solaris-era workstation graphics, so almost nothing outside legacy tools produces it today
- The common uncompressed variant carries no compression at all, so file sizes are large
- No metadata or colour profile fields
Open a RAS file when it comes from legacy Sun or Solaris workstation software, or from an old dataset captured directly off a SunOS framebuffer.
Convert RAS to PNG or TIFF for anything beyond archival viewing, since almost no current software or web platform accepts Sun Raster natively.
How to open a .ras file#
A .ras file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts RAS into a format your machine already opens, and it does it in the browser tab rather than on a server.
| Platform | Programs that open it |
|---|---|
| Windows | IrfanView, XnView, ImageMagick |
| macOS | ImageMagick |
| Linux | GIMP, ImageMagick, XnView |
| Web | FileFlip |
RAS questions people ask#
Is a RAS file the same as a SUN file?
Yes. A RAS file and a SUN file are the same Sun Raster format, identified by the same magic number and header layout, just saved under two different extensions that various tools have used over the years.
What software still opens RAS files?
ImageMagick, GIMP and viewers like IrfanView and XnView still read RAS files, since Sun Raster support has stayed in their format libraries even though the format itself dates to 1980s Sun workstations. Most mainstream photo apps and web browsers do not.
Why is my RAS file so large?
Most RAS files store pixel data uncompressed, since Sun Raster's optional run-length encoding was only ever one of several supported modes rather than the default. Converting to PNG or TIFF typically shrinks the same image considerably.
Converting RAS files#
Convert RAS to another format
- RAS to AsciiDoc
- RAS to AVIF
- RAS to BBCode
- RAS to BibTeX
- RAS to BMP
- RAS to BMP2
- RAS to BMP3
- RAS to CBZ
- RAS to Djot
- RAS to DocBook
- RAS to DOCX
- RAS to DokuWiki
- RAS to EPUB
- RAS to FB2
- RAS to GIF
- RAS to GIF87
- RAS to Haddock
- RAS to HDR
- RAS to HTML
- RAS to ICML
- RAS to ICO
- RAS to ICON
- RAS to IPYNB
- RAS to Jira
See every RAS conversion (36 more)
Convert another format to RAS
- 3FR to RAS
- ARW to RAS
- AsciiDoc to RAS
- AVIF to RAS
- BibTeX to RAS
- BMP to RAS
- BMP2 to RAS
- BMP3 to RAS
- CBZ to RAS
- CR2 to RAS
- CR3 to RAS
- Creole to RAS
- CRW to RAS
- DCR to RAS
- Djot to RAS
- DNG to RAS
- DocBook to RAS
- DOCX to RAS
- DokuWiki to RAS
- EPUB to RAS
- ERF to RAS
- FB2 to RAS
- GIF to RAS
- GIF87 to RAS
See every image conversion (61 more)
Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.