RAS to PJPEG Converter
FileFlip converts RAS to PJPEG 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 PJPEG?#
- 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 PJPEG 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 PJPEG file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting RAS to PJPEG lose quality?#
Yes, once. RAS keeps everything and PJPEG does not, so this is the first time the file meets a lossy encoder. At high quality the difference is hard to see, and it is worth keeping the RAS original, because every later re-save of the PJPEG loses a little more.
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 PJPEG actually does to the file#
Converting RAS to PJPEG runs on ImageMagick, downloads 14.1 MB of WebAssembly the first time and nothing after that, encodes a lossless source with a lossy encoder for the first time.
| Engine | ImageMagick |
|---|---|
| Conversion path | One step: RAS → PJPEG |
| Downloaded to your browser | 14.1 MB, once, then cached by your browser |
| Quality | Lossy, first generation |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
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 PJPEG file?#
PJPEG is progressive JPEG, a JPEG encoding choice rather than a different file format, where the image is built up through several increasingly detailed scans across the whole picture instead of filling in top to bottom in one pass.
Choose progressive encoding for images shown over a slow or uncertain connection, where a quick blurry preview beats a slow top-down reveal.
Convert to baseline JPEG when a downstream tool or embedded device only supports the simpler sequential scan order.
RAS to PJPEG 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 PJPEG?
PJPEG is progressive JPEG, a JPEG file encoded in a handful of increasingly detailed scans instead of one pass from top to bottom. It's still a JPEG file, just encoded differently, and opens anywhere JPEG does.