EPUB to SUN Converter

Render EPUB pages as SUN raster images — free online

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Unix Compatible

EPUB pages become SUN raster images ready for legacy Solaris, SunOS, and Unix-based imaging workflows and toolchains.

Server-Powered

Conversion happens on Convertio cloud infrastructure — your local device stays free from any processing burden.

Instant Cleanup

EPUB uploads are removed right after conversion finishes. SUN output files are automatically deleted within 24 hours.

How to convert EPUB to SUN

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose sun or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your sun file right afterwards

About formats

EPUB (Electronic Publication) is an open ebook standard originally developed by the International Digital Publishing Forum (IDPF) and now maintained by the W3C following the organizations' merger in 2017. The first version carrying the EPUB name was approved in October 2007 as a successor to the Open eBook Publication Structure (OEBPS). An EPUB file is essentially a ZIP archive containing XHTML or HTML5 content documents, CSS stylesheets, images, fonts, and metadata organized according to the Open Packaging Format and Open Container Format specifications. The current major version, EPUB 3, supports reflowable and fixed-layout content, embedded multimedia, JavaScript interactivity, MathML equations, and rich accessibility features including semantic markup and media overlays for synchronized text and audio. A defining advantage is universal device support — unlike proprietary formats, EPUB works natively on virtually every non-Kindle e-reader, tablet, and reading application, from Apple Books and Google Play Books to Kobo and dozens of third-party apps. The reflowable text model is another core strength, automatically adapting pagination, font size, and margins to match any screen dimension and user preference. EPUB's open specification and active W3C stewardship ensure long-term preservation and vendor independence, making it the de facto standard for digital publishing across libraries, academic institutions, and commercial retailers worldwide.
Initial release: October 2007
SUN is a raster image format associated with Sun Microsystems workstations, encompassing both the Sun Raster format (.ras) and the Sun Icon format used for window system icons and cursors on SunOS and Solaris systems. Sun Raster files, identifiable by their 0x59a66a95 magic number, store bitmap images in 1-bit monochrome, 8-bit indexed color, 24-bit BGR, or 32-bit XBGR modes, with optional run-length encoding compression and a 32-byte header. The Sun Icon subset is a simpler text-based format used for small monochrome bitmaps — window icons, cursor images, and toolbar graphics — stored as C-language data arrays that could be directly compiled into X Window and SunView applications. These icon files begin with a comment block specifying width, height, and optionally hot spot coordinates (for cursor images), followed by hexadecimal pixel values in a format readable by both the C compiler and the iconedit tool. Sun workstations running SunOS and later Solaris were foundational platforms for Unix computing, networking, and the early internet, and the SUN image formats were integral to their graphical environments. One advantage is the format's dual text/binary nature: Sun Icons are valid C source code that can be #included directly into applications, a practical approach to resource embedding that predates modern asset management systems. The Sun Raster variant's simplicity provides another strength — the 32-byte header and straightforward encoding make it one of the easiest binary image formats to parse. SUN format files are supported by ImageMagick, GIMP, XnView, and Unix image viewing tools.
Developer: Sun Microsystems
Initial release: 1982

Frequently Asked Questions

Why convert EPUB to SUN?

SUN raster is an alternative extension for Sun Raster images — required by some legacy Unix tools that expect the .sun extension specifically.

What programs read SUN files?

ImageMagick, GIMP, XnView, and native Solaris/SunOS image viewers all handle SUN raster files without extra plugins.

Is SUN the same format as RAS?

SUN and RAS are alternate extensions for the same Sun Raster format. The underlying image data structure is identical.

Will my EPUB page text stay sharp?

Each page is rasterized at good resolution before encoding — text and graphics remain legible in the SUN output.

Is EPUB to SUN conversion free?

Yes, Convertio performs this conversion at no cost. Premium accounts are available for larger file sizes and priority processing.