SUN File Format (.sun)

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.

.sunImage Files

SUN at a glance#

Full name	SUN Rasterfile
File extension	.sun
Category	Image Files
Developer	Sun Microsystems
MIME types	image/x-sun-raster
Other extensions	.ras
Compression	Varies from file to file
FileFlip support	FileFlip reads and writes this format

Strengths and limitations of SUN#

What SUN does well

Byte-identical to the more common .ras files, so any Sun Raster decoder reads it without changes
Header carries width, height, depth and colormap fields, so an image reconstructs with no outside information
The optional run-length variant compresses flat areas like screen captures well

Where SUN falls short

The .sun extension is rare enough that some tools supporting .ras will not auto-detect a .sun file by name
No metadata, colour profile or transparency support
Superseded decades ago by TIFF and PNG for cross-platform raster work

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.

How to open a .sun file#

A .sun file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts SUN 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

SUN 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.

Converting SUN files#

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.