In coming months we will be profiling raw file conversion software that can substitute for Adobe Camera Raw and integrate effectively with an image editor. We’re doing this because even Adobe admits its change to Cloud-based subscriptions won’t suit semi-professional photographers, photo enthusiasts, hobbyists, retirees or anyone with a low – or unpredictable – income. This series of reviews begins with the latest version of RawTherapee.
After using RawTherapee 4.0.11 with raw files from several different camera manufacturers we are very impressed by its capabilities. You can view JPEG files and TIFF files from any source, including Sigma’s cameras and other raw file converters. And, even if you’re not processing raw files, JPEG and TIFF files can be tweaked with the tools provided in RawTherapee.
There are few adjustments you can’t make with the tools on offer, which are more extensive than those provided by most raw file processors. Live updating of the adjustments you apply makes it very easy to see how far to take each one. As a raw file converter, RawTherapee leaves little to be desired.
However, as an image editor it lacks some critical functions. If you like to make file conversions separately from editing adjustments and/or are prepared to move TIFF files converted with RawTherapee into the editor of your choice, this really doesn’t matter.
But if you require a fully-functional editor with an integrated raw file processor ““ like you get in Photoshop ““ RawTherapee may not suit you because it lacks selection tools and doesn’t support Layers. You can’t isolate an area within an image for separate adjustments.
And, while the application is being constantly updated to include new cameras as they are released, we found its profile listings lagged by a generation or two for most brands and missed out on Olympus altogether. (You can profile your own equipment to make up for these deficiencies.)
Rating
| Features | 9.0 |
| Ease of use | 9.0 |
| OVERALL | 9.0 |
RRP: Free
RawTherapee 4.0.11 is freeware, which means it is available to end-users as a download from the developers’ website and can be used free of charge, wherever you like on whatever hardware you like, provided you abide by the copyleft GPLv3 license (details here: https://www.gnu.org/copyleft/) . Under this licence, you can download the source code, modify it and share your experiences on the open forums on the RawTherapee blogsite (http://rawtherapee.com/forum/).
The developers recommend it be used on a 64-bit operating system to ensure stability. So that’s the platform we used, running our tests on a computer with an Intel Core i7 CPU with 8GB of RAM and Windows 7 operating system. You can also use RawTherapee 4.0.11 on computers running MacOS X or Linux.
What is It?
The RawTherapee project was started in 2004 by the Hungarian programmer, Gabor Horvath. In January 2010, Gabor decided to open his source code under the GNU General Public License and since then, developers from around the world have joined the project. Their efforts are on-going, with the latest version of RawTherapee providing a very sophisticated and capable raw file processor that can rival (or better) many existing programs.
Like almost all raw processors (proprietary and open source) RawTherapee 4.0.11 uses dcraw (another open source conversion program) to decode raw images ““ although not to process them. When dcraw adds support for a new camera, RawTherapee will also be updated. Readers with programming expertise can find out more about decoding raw images from this website: http://www.cybercom.net/~dcoffin/dcraw/, which has been set up by Dave Coffin, the developer of dcraw.
In this review we can only provide an overview of the capabilities of RawTherapee 4.0.11 because of the multitude of adjustments it provides. A comprehensive (105-page) user manual in PDF format is available from the same site for as you use for downloading the program. It explains all of the features of the program and provides easily understood instructions for using it.
There’s also a ‘live’ manual online that is being edited continuously as new features are added or existing functions adjusted. We recommend working through the manual in the early stages and exploring the options available.
The website provides plenty of information about using the software and reporting any bugs found. There’s also a guide to setting colours to match Nikon’s Capture NX 2 hues and tones plus a range of ‘Unofficial Tutorials’ provided by community members.
Who’s it For?
This program is designed for serious raw file shooters; not for those who only shoot raw files occasionally or those who aren’t interested in tweaking their files to gain the best results. If you are an imaging geek, you should take a close look at this powerful application.
Support is provided for most cameras that use conventional sensors ““ but not for Foveon chips. So if you own a Sigma camera you will need to convert the X3F raw files from it with Sigma’s raw file converter.
How it Works
When you download the application, installing it from the zipped file should be straightforward. The program should install with other programs on your hard drive. Installation creates a cache folder for storing the processing profile for each image. It’s identified by a ‘pp3’ suffix and is similar to the sidecar files used by Adobe for storing raw file development parameters.
Like other non-destructive editors, RawTherapee creates ‘sidecar’ files containing details of all the adjustments made when you processed each raw file. Each sidecar file is stored with the related image file using the same filename ““ but a different extension (*.pp3). When you re-open a processed raw file in RawTherapee, the sidecar file will be read and all the settings from the last session will be restored.
PP3 files are written each time you close a photo or close RawTherapee. By default, this information is also saved to a cache on your hard disk. You can also force saving the processing profile of the photo you are working on by hitting the Ctrl+Shift+S keyboard shortcut.
Using RawTherapee 4.0.11
The first time you start RawTherapee an empty file browser tab will appear because you need to tell RawTherapee where your raw photos are stored. Once the folder is selected, RawTherapee will read each file and generate thumbnails of your photos in the central panel. Subsequent openings of RawTherapee will display the browser for the last folder you worked with.
The Preferences window, which is accessed via a button in the top right corner of the workspace, lets you can up RawTherapee to suit your preferences. There are seven pages within this menu, covering general settings for the background colour, layout and links to an external editor as well as pages for image processing, file browsing, colour management, batch processing, performance and sounds parameters.
Double-clicking on a thumbnail opens the selected image file and launches the Editor toolbox on the right side of the workspace. A History panel on the left of the workspace tracks all of the adjustments made to the selected image file.
The Editor toolbar provides five preview modes to help you tweak images. (They are also available via keyboard shortcuts.) Only one preview mode can be engaged at a time and options available include separate previews for the red, green, blue and luminosity channels plus a focus mask preview for seeing which areas are in focus.
Previewing individual channels can be helpful when editing RGB curves, planning black/white conversion using the channel mixer or evaluating image noise, while the luminosity preview provides an instant view in black and white without altering development parameters. It’s handy for seeing how images appear in monochrome as well as for picking up which channel might be clipping.
RawTherapee comes with a collection of 32 ‘processing profiles’ that enable users to start with a particular ‘look’, which can be modified, if required. A Custom setting is provided for creating and storing your own profiles. You can store processing profiles with the input file (image) or in a separate cache. The former is recommended as it means the profile travels with the image when it is copied or stored.
All the adjustments you could ask for are available in the Editor toolbox. The Exposure tab opens a panel with an Auto Levels button plus sliders for tweaking exposure values. You can reset all of the sliders in the Exposure section by clicking on the Neutral button. This panel also contains sliders for adjusting contrast, saturation, shadows/highlights balance and tone curves, the latter including film simulation.
The second tab in the Editor toolbox is the Detail tab, which provides adjustments for sharpening and noise reduction. The effects of some of the filters in this panel can only be seen when the image is magnified to 100%.
Sharpening in RawTherapee can be done by two methods: Unsharp Mask (USM) or RL Deconvolution. Unsharp masking uses the standard adjustment parameters of Radius, Amount and Threshold but the software allows you to apply it to only edges to prevent over-sharpening of noise-affected areas. You can set the edge tolerance (how much a pixel has to differ from its neighbour to be considered as an edge) and engage Halo Control to minimise halo effects around bright areas.
RL Deconvolution applies a filter that counteracts Gaussian blur. You can define the Radius of the Gaussian blur you want to remove and use the Damping slider to prevent sharpening of noise on smooth areas. Since deconvolution requires several Iterations for success, the number of iterations is also adjustable.
Noise Reduction adjustments rely on wavelets and a Fourier transform and this is one tool that requires 100% magnification to see the effects. Separate sliders are provided for controlling Luminance (brightness) and Chrominance (colour) noise as well as ‘Delta Chrominance’ sliders for the red and blue channels.
The Gamma slider varies noise reduction strength across the range of tones, enabling users to work selectively on different tonal levels. The Defringe tool is for correcting coloured fringing caused by axial (or longitudinal) chromatic aberration.
The Colour tab is next in line. It contains adjustments for white balance and Vibrance plus a Channel Mixer, HSV Equaliser and RGB Curves adjustments. An eyedropper is provided for sampling a neutral area in the image. Alternatively, you can access a drop-down menu of camera light source pre-sets. The user manual provides a list of equivalent Kelvin temperatures for different camera brands.
Vibrance adjustments are more controllable than in most raw processors, with the ability to balance saturated hues against pastel tones plus a check box for protecting skin tones against over-processing. You can also access pre-set curves for different skin renditions.
The Channel Mixer allows separate adjustments of the Red, Green and Blue colour channels. It is used to extend the range of White Balance tool and also for manipulating tones in IR and black & white photographs. Another selective colour adjuster is the HSV (Hue, Saturation and Value) Equaliser, which can be used to make one colour stand out without affecting others. RGB curves allow users to apply a curve adjustment individually to each of the RGB channels.
The Colour Management section is designed for use with ICC and Adobe DCP profiles. The default setting is auto matched to the camera-specific profile, which works when the camera can be retrieved automatically from the /dcpprofiles or /iccprofiles directory in the computer. Users can also specify a custom DCP or ICC camera input profile.
If no profiles are available, RawTherapee provides a set of profiles, based on different types of lighting (daylight, tungsten, fluorescent or flash). You can also specify the working colour space from seven options, including sRGB and Adobe RGB.
Next in line comes the Transform tab, which contains cropping, re-sizing, rotating, lens adjustments plus tools for perspective control and correcting distortion, chromatic aberration and vignetting correction. You are taken to this tab automatically if you select the cropping or straightening tool in the top toolbar.
The next tab is the Raw tab, which provides tools designed specifically for processing raw files. The first section lets you select the Demosaicing algorithm for unpacking the raw information. RawTherapee uses the Fast algorithm initially but, from there you can choose from nine algorithms. AMaZE (Aliasing Minimization and Zipper Elimination) is the default method, as it yields the best results in most cases.
The Raw tab also contains Preprocessing settings for filtering pattern noise and suppressing interpolation artefacts produces by some cameras with slightly different green filters in the two green channels of the colour filter array. There’s also a filter for eliminating ‘hot’ or ‘dead’ pixels.
Linear correction sliders are provided for correcting the black and white points to deal with difficult lighting. Dark Frame correction is also provided for dealing with unevenness in long exposures. Similarly, the Flat Field correction lets you compensate for non-uniform lighting. Chromatic aberration correction is also available.
The final tab is the Metadata tab, which displays the Exif metadata recorded in the image. You can Remove, Keep, or Add/Edit Exif metadata. An additional tab in this section is for IPTC metadata covering information about the image, such as a title, location, keywords for searching and copyright information.
Other Features
RawTherapee can be used for batch processing. When you select two or more image files while holding down the Shift or Control key, you can edit them together. In this mode, you can modify the ways the sliders behave using the options provided in the Batch Processing tab in the Preferences tool.
The default setting is for all sliders to be in the Set mode, which means the value of the slider is locked in to the corresponding parameter and all images in the batch will receive the same adjustment. In the Add mode, you can modify the range and value of the slider differently for the selected images. For example, if one image has an ‘Exposure compensation’ of -0,5 EV, and another one which has an Exposure compensation of +1,0 EV, moving the slider up to 0,3 will result in setting a value of -0,2 EV for the first image and +1,3 EV for the second one.
Unfortunately, the selection process is a bit clumsy and it’s almost impossible to select two raw files from a folder containing a mixture of file types. We found it best to rate the images we wanted with the same number of stars and then use the top toolbar to select only the rated images, which could then be selected for batch editing in the recommended way.
Once you have finished working on an image (or batch of images) you can move them into a processing queue with a button in the bottom left corner of the central panel. A button to the left of this button causes the image to be processed and saved, while a button to its right sends the file to an external editor.
RawTherapee needs to know which program you want to use so you have to select the editor in the General panel in the Preferences menu. We were unable to get this function to work with Photoshop CS6, despite trying a number of different ways of ‘telling’ RawTherapee where the program was located.
It’s not an essential feature, since RawTherapee lets you save processed images as 16-bit TIFF files in the same directory as the original raw files. And it’s easy to open these TIFFs in Photoshop ““ or any other image editor.
Conclusion
After using RawTherapee 4.0.11 with raw files from several different camera manufacturers we are very impressed by its capabilities. You can view JPEG files and TIFF files from any source, including Sigma’s cameras and other raw file converters. And, even if you’re not processing raw files, JPEG and TIFF files can be tweaked with the tools provided in RawTherapee.
There are few adjustments you can’t make with the tools on offer, which are more extensive than those provided by most raw file processors. Live updating of the adjustments you apply makes it very easy to see how far to take each one. As a raw file converter, RawTherapee leaves little to be desired.
However, as an image editor it lacks some critical functions. If you like to make file conversions separately from editing adjustments and/or are prepared to move TIFF files converted with RawTherapee into the editor of your choice, this really doesn’t matter.
But if you require a fully-functional editor with an integrated raw file processor ““ like you get in Photoshop ““ RawTherapee may not suit you because it lacks selection tools and doesn’t support Layers. You can’t isolate an area within an image for separate adjustments.
And, while the application is being constantly updated to include new cameras as they are released, we found its profile listings lagged by a generation or two for most brands and missed out on Olympus altogether. (You can profile your own equipment to make up for these deficiencies.)