SUN to CBZ Converter
FileFlip converts SUN to CBZ entirely inside your browser, using ImageMagick and MuPDF 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 SUN file to CBZ?#
- Drop your SUN 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 CBZ and the conversion starts on its own. FileFlip downloads 24.1 MB of WebAssembly the first time and nothing after that, then runs ImageMagick and MuPDF on your own machine.
- Save the CBZ file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting SUN to CBZ lose quality?#
No. The SUN picture is placed into the CBZ document at its full resolution, so every pixel reaches it intact. What you give up is that it becomes a picture inside a document rather than text.
Is it safe to convert SUN files online?#
Yes, because nothing is uploaded. FileFlip converts SUN 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 SUN to CBZ actually does to the file#
Converting SUN to CBZ runs on ImageMagick and MuPDF, downloads 24.1 MB of WebAssembly the first time and nothing after that, places the picture into the document at full resolution.
| Engine | ImageMagick and MuPDF |
|---|---|
| Conversion path | 2 steps: SUN → PNG → CBZ |
| Downloaded to your browser | 24.1 MB, once, then cached by your browser |
| Quality | Pixels preserved |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
Worth knowing before you start:
- the picture is placed in the document as a picture; no text is recognised out of it
What is a SUN file?#
A SUN file is a Sun Raster bitmap, the same raw framebuffer image format Sun Microsystems shipped on SunOS workstations, saved under the alternate .sun extension some raster-image tools use in place of the identical .ras.
Recognise a .sun file as a Sun Raster image if it turns up alongside .ras files from the same legacy Solaris export or archive.
Convert SUN to PNG or TIFF for any modern use, since the .sun extension gets even less software recognition than .ras.
What is a CBZ file?#
A CBZ file is a ZIP archive of page images, usually JPEG or PNG, named so they sort into reading order, with nothing else defining it as a comic beyond that convention.
Use CBZ to distribute a scanned or digital comic as sequential page images that any comic reader opens without conversion.
Convert CBZ to PDF when a comic needs to move into software that expects a page-based document instead of a folder of images.
SUN to CBZ questions people ask#
What is a SUN file?
A SUN file is a Sun Raster bitmap, the simple framebuffer image format Sun Microsystems used on SunOS and Solaris workstations, identified by a fixed magic number at the start of the file rather than by its extension.
Is SUN the same format as RAS?
Yes, a SUN file and a RAS file are the identical Sun Raster format. The two extensions exist because different tools over the years registered the format under different names, not because the files differ in any way.
Can I just rename a .sun file to .ras?
Renaming a .sun file to .ras works, because the two extensions point at the same byte-for-byte format and most decoders identify a Sun Raster file by its magic number rather than its extension. Some tools that only recognise .ras will open the renamed file without issue.
What is a CBZ file?
A CBZ file is a ZIP archive holding a comic's pages as individual image files, named so they sort into the right reading order. There is no page-layout data or text encoding involved, which is the entire format: a comic reader just opens the ZIP and displays the images in sequence.