RAS to SIXEL Converter
FileFlip converts RAS to SIXEL entirely inside your browser, using ImageMagick compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert a RAS file to SIXEL?#
- Drop your RAS file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to SIXEL and the conversion starts on its own. FileFlip downloads 14.1 MB of WebAssembly the first time and nothing after that, then runs ImageMagick on your own machine.
- Save the SIXEL file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting RAS to SIXEL lose quality?#
No. Converting RAS to SIXEL writes the data out again without discarding any of it, so nothing that was in the RAS file is lost on the way. What changes is the size of the file, not what is inside it.
Is it safe to convert RAS files online?#
Yes, because nothing is uploaded. FileFlip converts RAS files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What RAS to SIXEL actually does to the file#
Converting RAS to SIXEL runs on ImageMagick, downloads 14.1 MB of WebAssembly the first time and nothing after that, writes the data out again without discarding any of it.
| Engine | ImageMagick |
|---|---|
| Conversion path | One step: RAS → SIXEL |
| Downloaded to your browser | 14.1 MB, once, then cached by your browser |
| Quality | Lossless |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
Worth knowing before you start:
- the target holds at most 256 colours, so a full-colour image is quantised to a palette
What is a RAS file?#
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.
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.
What is a SIXEL file?#
A SIXEL file holds a bitmap encoded entirely as printable ASCII characters, using DEC's six-pixel-tall encoding scheme, so it can be sent to a printer or terminal over a plain 7-bit serial link and displayed without any separate image protocol.
Use Sixel when an image needs to display inline inside a terminal session, such as showing a chart or a thumbnail over SSH without opening a separate viewer.
Convert a Sixel image to PNG once it needs to be viewed anywhere outside a terminal emulator that understands the encoding.
RAS to SIXEL 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.
What is a SIXEL file?
A SIXEL file is a bitmap image encoded as printable ASCII text using DEC's six-pixel-tall scheme, originally built in the early 1980s so DEC printers and terminals could receive graphics over the same serial link used for plain text.