You don’t need to have played with a digital SLR camera for long to run into the continuing frustration that is RAW images. RAW images offer very high image quality without the nasty compression artifacts of often found in consumer cameras using the JPEG format.
The problem though is that there is no one definition of RAW – it’s more a file format than a defined compression or “codec” so each camera manufacturer is free to come up with their own interpretation. That means its virtually impossible to find any image editor – free image editor – that comes with decent RAW support.
But that doesn’t mean all hope is lost. In fact, in the Linux world, the community has done a terrific job of supporting digital camera enthusiasts – arguably even better than its Windows counterpart – with RAW tools that not only decode RAW images from various camera makes but also converting them into more generic file formats such as TIF and BMP.
Here’s our list of ten free RAW image tools available for the Linux platform
While this isn’t strictly a RAW-specific tool, you’ll need a tool to get the images out of your camera and unless you have a flash memory card reader, you’re going to need something like gPhoto2. gPhoto2 is the command-line interface to the libgphoto library that has support for over 1000 digital cameras at last count.
Not only does it detect and extract files direct from your digital camera, it can also be used to capture images or video remotely from your camera, turning it into a basic webcam.
gPhoto2 can’t do anything in the way of image processing but if you need to get images, movies or audio out of your camera’s internal memory, gPhoto2 is about as good as it gets.
Okay, this isn’t strictly a Linux tool but it’s an absolute must-have if you own a Canon camera. CHDK RAW is basically a firmware hack that brings out the RAW capabilities of Canon cameras using the DiGIC II and III processors. So even if you have a low-end PowerShot A610, you can move up from the camera’s JPEG image capture and get it to capture in RAW mode instead.
The nice thing about CHDK is that although it does change your camera when loaded, you only need to remove the flash card the BIOS hack is loaded onto in the first place, reboot the camera and it’s back to normal. The firmware hack enables other features such as histogram views and lots of other useful bits that Canon doesn’t give by default.
Okay, now into the RAW stuff proper. DCraw is arguably the best known of the RAW libraries for Linux and it’s the one used by a truckload of front-ends or “user interfaces”. The trick here is to look for a user interface that suits what you want to do and has implemented the right DCraw features you need. DCraw comes as the basic C-language source code, which you then compile into your desired platform. Windows and Mac OS X users can find executable/binary files via the DCraw website. You’ll find a good list of examples here.
If you prefer working with command-line tools, DCraw is about as good as it gets but there are plenty of graphical user interface tools around that will make this tool a breeze for those who hate command prompts.
UFRaw is short for “unidentified flying RAW” and basically picks up where DCraw leaves off. That might be a bit harsh on DCraw but UFRaw has the advantage of being a plugin for GIMP and the ability to work around GIMP’s 8-bit limitation by being able to do its processing in 16-bit per colour channel. UFRaw is infact built on DCraw however, the good news is you don’t have to compile it – there are packages available for most of the major distros such as Ubuntu, Fedora and Gentoo.
But don’t think UFRaw is just a plugin for GIMP – it’s a stand-alone tool as well so if using a command-line isn’t your bag, UFRaw is an option well worth looking at.
RawStudio is similar to UFRaw but another tool based on DCRaw. This one will recognised any RAW image file format supported by UFRaw and convert it into something a little more common such as such as JPEG or TIFF (although why you’d want to go straight to JPEG beats me). It features a neat user interface and allows for batch file processing, a handy feature if you have 50 RAW images to process.
It gives you a decent range of controls over images in terms of white balancing, saturation plus basic editing such as cropping and straightening.
The list of supported cameras is not exclusive so you should be able to get RAW shots from modded Canon PowerShot models to work here. There are pre-built packages available for Mac OS X, Ubuntu and OpenSUSE but for those wanting the latest, there are daily subversion checkouts (source code) available for your compiling pleasure (compiling commands are also given.)
RawTherapee is yet another front-end tool for DCraw however it has a few extra features you won’t find in RawStudio including lens distortion and chromatic aberration correction tools. I think the interface of RawTherapee is just a little better than RawStudio with a better layout of its controls but that’s just me.
What is impressive about this one is that it has been ported by the developer into a Windows version as well as the original Linux version. It has support for Intel’s SSE extensions (extension extensions?) to help speed processing along. The Windows version works on anything from Windows 2000 and up while the Linux version just needs GTK+ 2.12 or better and gtkmm 2.14 or better.
DigiKam is arguably the most well-known of the image tools we’ve looked at so far but it has support for RAW image file processing thanks to its use of libkdcraw, which is part of the KIPI project (KDE Image Plugin Interface). So that means digiKam can do pretty much anything dcraw can do – and if it can’t, you can always add it in yourself because the source code for libkdcraw is available for your use.
DigiKam is as much a photo management tool as it is an editor so while it might not have the horsepower of RawTherapee for example, it has enough basic features for general users to stay happy. But you’d want to give RawTherapee a go first.
Google’s Picasa isn’t strictly a Linux tool although it runs via its own bundled version of WINE (Windows compatibility layer) tool. But thanks to DCRaw, it supports RAW image formats. Picasa is in a sense Google’s version of DigiKam – they’re both reasonably similar in that they manage as much as they edit. However, having to use WINE is a bit clunky, surprisingly so for Google, and there are better native Linux tools to choose from before you need to give Picasa a go.
Picasa 3 Beta is currently available as pre-built packages for Red Hat/Fedora and Debian. It’s a 30MB download, of which, only 13MB is actual “Picasa”. The rest is WINE and the gecko engine.
RawView is a new implementation of RAW image support via a library designed for Java. Although the author describes this one as a “work in progress”, there have been no updates since 2005, however the website and download files are still available. Since it has been updated in some time, it won’t support every RAW image file format available but at least it’s something if you must absolutely work in Java.
The lastest Linux installer version dates back to the end of 2004 although a no-install generic Java release of a beta version came out in early 2005.
Qtpfsgui is a workflow tool designed for HDR (high dynamic range) imaging. HDRI is all about trying to capture greater differences between white and black than you’d normally get in digital photography so as to create more life-like images. One of its tricks is the ablity to create an HDR image from a set of standard images captured at different exposure settings. It can then carry out basic editing (resize, crop etc).
It’s available for Windows, Mac OS X and of course, Linux. You can pick it up as source code but there are various pre-built packages around for the major Linux distros.
No doubt, there are a few we haven’t included in this list. There are a truckload of closed-source or commercially available tools that will tear RAW images to shread and glue them back together however, these 10 tools should cover most needs, regardless of whether you’re a command-line or GUI kind of user.
If we have missed any important tools, please drop us a note below.
And what about Bibble? It’s probably the best and professional RAW tool for Linux.
Yeah, we thought about Bibble – but is it still free?