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RAW converter for linux

Now that I have a Linux server running (actually been running for a few years), I have been using Linux a lot! A few days ago, I shot some pictures for my web-site with my Canon EOS D30. Normally, I shoot in RAW mode for my fine art pictures and switch to low-res jpeg mode for my technical web pictures. So I made a booboo and forgot to switch this time around.

Today I wanted to put these picturse on my web-site. But I can't operate on them directly. So I gotta do RAW conversion for these photos. And I happen to be using Linux, so I wanted to convert on Linux as well.

I managed to find a small linux source code called dcraw.c . . . you can download it at "Raw Digital Photo Decoding in Linux". Compiling it was a snap by using the following command:

gcc -o dcraw -O3 dcraw.c -lm -ljpeg

It generates an equally small executable called dcraw, which I placed in my bin path. Using it is even slicker. Just type the following command in the directory where conversion is to be done:

dcraw *.crw

And it would generate all the PPM files automatically with all the right names! And if you remember to use the '&' at the end of the line, it can process the images in the background while you work away on the command-line:

dcraw *.crw &

By the way, this utility can process RAW files from many different camera manufacturers, such as Canon, Nikon, Casio, etc. If you don't think your camera can produce RAW files, you might consider visiting that page. It has links to other sites that will show you how to enable RAW imaging in cameras that do not officially support the RAW format.

Good luck.

Chieh Cheng
Thu Oct 14 16:52:00 PDT 2004

When I posted about Raw Photo Decoder "dcraw", it was at version 6.08. Now v7.77 is available. Remember to download the latest version.

Chieh Cheng
Fri, 14 Oct 2005 17:30:59 -0700

I just wanted to add that the compile command that worked on my Debian box was:
gcc -O3 -o dcraw dcraw.c -lm -ljpeg -llcms

I had to install some libraries first. So I did (as root)

apt-get install libjpeg62-dev
apt-get install liblcms1-dev

Good luck.

John A.
Sat, 4 Mar 2006 12:53:40 -0800


I'm wondering whether it's possible to get
a raw file out of a standard image format such as jpg, png, ....
If yes, how to do so?


Thu, 16 Mar 2006 01:17:43 -0800

eric, I believe that is impossible, because a raw to jpg/png conversion would cause some raw data to be thrown away. And I think a lot of that data cannot be reconstructed, even through analysis.

However, I am not a raw converter expert, so I will pitch the question to the guru, Dave Coffin, the author of dcraw.

Chieh Cheng
Thu, 16 Mar 2006 17:32:54 -0800


Here is Dave's response:

"Your answer is correct. There is no way to recover the original raw data from a JPEG file. Too much information has been thrown away.

"If you could recover the raw data, there would be no reason to shoot raw, as JPEG files are much smaller."

Chieh Cheng
Fri, 17 Mar 2006 00:46:15 -0800

but there is a way to conver say a jpg image into a raw image, "adding" or aproximating the missing data on the jpg?

thank you

Thu, 25 May 2006 18:47:58 -0700

Yes there is a way, I'm not entirely sure that it works quite as expected but maybe worth investigating..

Use the Stream command-line tool from ImageMagick.

Noel da Costa
Wed, 23 Aug 2006 08:24:39 -0700

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Title: free RAW converter for Linux, Mac OS, and Windows
Weblog: Camera Hacker
Excerpt: Today, I stumbled upon Unidentified Flying Raw (UFRaw). UFRaw is an utility to read and manipulate raw images, using Dave Coffin's DCRaw algorithm. This utility can be used on its own or as a Gimp plug-in. Because DCRaw already works as a stand-alone converter, this utility might have limited use . . .
Tracked: Thu, 20 Oct 2005 17:00:12 -0700

Title: Confused about RAW
Weblog: Camera Hacker
Excerpt: You know, this RAW thing has confused me forever. I still can't make sense of it. For instance, I have the Rebel, and when I use the Canon Browser to select photos from my camera... and when I view the photo properties, it's always described as a jpeg. I have the option after I open it to save it ma . . .
Tracked: Thu, 12 Jan 2006 11:35:42 -0800

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