BMP to RAF Converter
Convert BMP to RAF in your browser. You download a Linear DNG (.dng), not a .raf: only a Fujifilm camera can create a genuine RAF, and every editor that opens RAF also opens DNG. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
BMP expected · other image formats also work
How to use BMP to RAF
- 1
Add your BMP files: drop them here, choose them, or paste from the clipboard.
- 2
Pick the colour that replaces transparent areas, since DNG has none.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .dng files one at a time or together as a ZIP.
Why use Aback Images for bmp to raf
Where a RAF would go
RAF files are opened by Fujifilm X RAW Studio, Lightroom, Photoshop Camera Raw, Capture One and darktable, and every one of them opens the DNG too.
DNG next to BMP
The DNG is written uncompressed, so expect it to be several times larger than the BMP, which stores usually none; RLE for some 4 and 8-bit files.
Written without a lossy pass
The DNG is written uncompressed, so the pixels decoded from the BMP 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.
BMP vs RAF
What changes from BMP to RAF
Encoding: the BMP uses usually none; RLE for some 4 and 8-bit files; RAF uses uncompressed or lossless compressed sensor data in Fujifilm's own container, and the download is a Linear DNG: demosaiced 8-bit RGB with the colour matrices raw editors need.
Bit depth: 1, 4, 8, 16, 24 or 32 bits per pixel in the BMP; RAF allows 12 to 16 bits per channel depending on the camera, and the DNG written here has 8 bits per channel, linearised.
Colour: RGB or an indexed palette in the BMP; RAF supports camera RGB from an X-Trans 6×6 or Bayer 2×2 mosaic, written here as 8-bit sRGB.
Transparency: the BMP stores it as an optional fourth byte in 32-bit files, which many programs ignore; the DNG has none, so transparent areas are filled with the colour you choose.
Metadata: the BMP can carry nothing beyond the header's resolution fields (and a colour profile in rare V5 headers); RAF can carry EXIF and Fujifilm maker notes, including the Film Simulation, but nothing is copied across.
About BMP
BMP stores raw, uncompressed pixels. Files are huge but trivially simple, which is why some legacy Windows software, embedded displays and printers still ask for it.
A BMP is a 14-byte file header ('BM' and the offset to the pixels), a DIB header (40 bytes, or 108 and 124 bytes in the V4 and V5 versions that add colour masks and alpha), an optional palette, then pixel rows padded to 4 bytes and normally stored bottom-up.
BMP files usually come from Windows Paint, legacy Windows programs, embedded displays and some scanners.
About RAF
RAF is the raw format of Fujifilm cameras, from the X series to the medium-format GFX. Most X-series bodies use an X-Trans sensor with a 6×6 colour filter pattern instead of the usual Bayer 2×2.
RAF is not TIFF at the top level: it opens with the text 'FUJIFILMCCD-RAW', then a header with the camera model and offsets to three blocks: a JPEG preview near the start of the file, a header describing the sensor layout, and the sensor data.
RAF files come from Fujifilm X-T, X-H, X-S, X-E, X100 and GFX cameras.
When converting BMP to RAF makes sense
Forms and workflows that ask for RAF usually feed a raw editor, and each of those opens DNG as well, so the DNG can take the RAF's place. Keep the BMP if you only need to view or share the picture.
What RAF offers when it comes straight from the camera: Film Simulation baked into the embedded JPEG; Lossless compressed option on recent bodies; Large medium-format files from GFX cameras. Its drawbacks: Fujifilm's own container rather than TIFF; X-Trans demosaicing differs between raw editors; Film Simulations need camera-matching profiles in third-party editors.
Limitations
- BMP stores nearly every pixel literally, so almost any compressed target is several times smaller.
- A 32-bit BMP can carry an alpha byte that most programs ignore; if the image suddenly gains transparent areas after converting, that byte was set.
- The DNG holds the decoded 8-bit pixels, so it adds no dynamic range or detail beyond the BMP.
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Frequently asked questions
Why do I get a .dng file instead of a .raf?
A real RAF is written by Fujifilm cameras and holds the sensor's own readings (12 to 16 bits per channel depending on the camera, stored as uncompressed or lossless compressed sensor data in Fujifilm's own container) along with EXIF and Fujifilm maker notes, including the Film Simulation. A BMP holds no sensor data, so no software outside the camera can create a genuine RAF. The Linear DNG you get instead is Adobe's open raw format, and every editor that opens RAF files opens it with the same raw controls. It holds decoded pixels, so it adds no quality or dynamic range.
Does converting BMP to RAF lose quality?
DNG is written uncompressed, so the pixels are stored exactly as decoded.
What happens to transparency when converting BMP to RAF?
BMP stores transparency as an optional fourth byte in 32-bit files, which many programs ignore. DNG has no alpha channel, so transparent pixels are composited onto a solid colour, white unless you pick another. To keep transparency, convert to PNG, WebP or AVIF instead.
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.