What is a .raw file?
Camera RAW image · Image · Camera makers (Canon, Nikon, Sony, Adobe) · 1990s onward
RAW is not one format but a family of camera files that store the sensor's unprocessed data. That gives photographers huge latitude to adjust exposure and colour later, at the cost of large files and the need for editing software.
What is a .raw file used for?
A RAW file is the digital equivalent of a film negative. It records what the sensor captured before the camera applied sharpening, white balance or compression, so nearly everything can be changed afterward without loss.
Each maker uses its own variant, so Canon shoots CR2 or CR3, Nikon shoots NEF and Sony shoots ARW. Adobe's DNG is an open RAW format meant to work across brands.
Because RAW is unprocessed, you develop it in software like Lightroom, Capture One or the free darktable, then export a JPG or TIFF.
What opens a .raw file?
The .raw format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- Lightroom
- darktable
- RawTherapee
- Photos (with codec)
macOS
- Photos
- Lightroom
- Preview
- Capture One
Linux
- darktable
- RawTherapee
- GIMP
Web
- Convert to JPG or TIFF first
Open a .raw file step by step
- Confirm the file really is a .raw. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with Lightroom or darktable.
- On Mac, use Photos or Lightroom.
- On Linux, try darktable or RawTherapee.
- Still stuck? Convert the .raw to JPG, which opens more widely.
Why can't I open my .raw file?
Almost always because no installed app understands RAW. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .raw at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
How to convert a .raw file
You can convert a .raw file to JPG, TIFF, PNG, DNG.
Darktable and RawTherapee are the free developers for camera raw. Export to JPG for sharing or to DNG to keep the raw data in an archival container. A JPG export bakes in the white balance and exposure, so you cannot go back.
What is the .raw file signature (magic bytes)?
A .raw file starts with the hex bytes 49 49 2A 00, which read as II*. in ASCII. Other formats open with the same bytes, so they narrow a file down without proving it is RAW. Programs confirm the format from the tags and structure that follow the header, not from these bytes alone.
These are the documented signatures for RAW.
| Hex signature | Offset | ASCII | Note |
|---|---|---|---|
| 49 49 2A 00 | 0 | II*. | TIFF-based RAW only (CR2, NEF, DNG) |
| 4D 4D 00 2A | 0 | MM.* | big-endian TIFF-based RAW |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .raw file?
RAW is not one format but a family of camera files that store the sensor's unprocessed data. That gives photographers huge latitude to adjust exposure and colour later, at the cost of large files and the need for editing software.
Why can't I open my camera RAW file?
Your viewer may not have the codec for that camera model. Use Lightroom, RawTherapee or darktable, or convert the file to DNG or JPG.