RAS to PNG Converter
Convert RAS to PNG in your browser. RAS files usually come from SunOS and Solaris workstations, old Unix screen dumps and scientific software; PNG is the better fit for screenshots, logos, graphics and anything that needs transparency. You get a lossless 8-bit PNG with full alpha. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
RAS expected · other image formats also work
How to use RAS to PNG
- 1
Add your RAS files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the PNG is written losslessly. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .png files one at a time or together as a ZIP.
Why use Aback Images for ras to png
Where the PNG goes next
PNG opens in every browser, operating system and image editor.
PNG next to RAS
Both sides are lossless, so the size depends on how well the PNG encoder handles this picture compared with the RAS's none or a byte-oriented run-length encoding (RT_BYTE_ENCODED).
Written without a lossy pass
The PNG is written losslessly, so the pixels decoded from the RAS arrive unchanged.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
RAS vs PNG
What changes from RAS to PNG
Encoding: the RAS uses none or a byte-oriented run-length encoding (RT_BYTE_ENCODED); PNG uses lossless DEFLATE with a prediction filter chosen per row, and the download is a lossless 8-bit PNG with full alpha.
Bit depth: 1, 8, 24 or 32 bits per pixel in the RAS; PNG allows 1, 2, 4, 8 or 16 bits per channel, and the PNG written here has 8 bits per channel.
Colour: monochrome, a colour map, or RGB stored as BGR in the RAS; PNG supports RGB, greyscale, or an indexed palette of up to 256 colours, written here as 8-bit sRGB.
Metadata: the RAS can carry only a 32-byte header with size, depth, type and colour map length; PNG can carry text chunks, an ICC profile, physical resolution and EXIF in an eXIf chunk, but nothing is copied across.
About RAS
Sun Raster is the bitmap format of Sun Microsystems' SunOS and Solaris workstations. It stores 1, 8, 24 or 32-bit pixels, optionally with a colour map and simple run-length compression.
A Sun Raster file starts with the magic number 59 A6 6A 95 and a 32-byte header (width, height, depth, data length, type, colour map type and length), then the colour map and the rows, each padded to an even number of bytes.
RAS files usually come from SunOS and Solaris workstations, old Unix screen dumps and scientific software.
About PNG
PNG stores pixels losslessly with full alpha transparency. It is ideal for screenshots, logos, UI and anything with sharp edges, but photos saved as PNG are several times larger than JPEG.
A PNG opens with an 8-byte signature and is a chain of chunks, each with its own CRC: IHDR (size, depth, colour type), optional PLTE and tRNS for palettes, one or more IDAT chunks with the compressed rows, and IEND.
When converting RAS to PNG makes sense
PNG is the better choice for screenshots, logos, graphics and anything that needs transparency, while RAS suits legacy Sun and Unix software.
PNG strengths: Lossless: no quality loss, ever; Full transparency with smooth edges; Perfect for text, screenshots and graphics. Drawbacks to weigh: Large files for photographs; No standard animation (that is APNG).
Limitations
- Standard Sun Raster files store 24-bit pixels in blue, green, red order; the decoder swaps them, so colours come out right.
- A PNG of a photograph is often several times larger than a JPG; PNG pays off for screenshots, graphics and anything with transparency.
- The PNG is written in full colour; Compress PNG can shrink it further with a palette.
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Frequently asked questions
Does converting RAS to PNG lose quality?
PNG is written losslessly, so the pixels are stored exactly as decoded.
Which apps open PNG files?
Every browser, operating system and image editor.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.