RawTherapee is a powerful cross-platform raw image processing program, released under the GNU General Public License Version 3. Started in 2005 by Gábor Horváth, it was released as open-source software in 2010 and has been under development by an international team ever since. RawTherapee has an extensive set of tools specifically aimed at processing photographs. It works very well in conjunction with raster graphics editors, such as Photoshop or GIMP, and a digital asset manager, such as digiKam.
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When you start RawTherapee you will land in the File Browser tab, and it might be empty. You need to point RawTherapee to where your raw photos are stored. Use the folder tree browser on the left of the File Browser tab to navigate to your raw photo repository and double-click on the folder to open it. Then double-click on a raw photo to start editing it.
Edit your first image
First, a little background. A raw photo contains a dump of sensor data, which makes up the bulk of the raw file. This sensor data does not look like a pretty image, in fact it does not look like anything - it is "raw" data, ergo the name. It must be "cooked" to look like the image you saw through the viewfinder. Your camera cooks the raw data into a pretty image, which it stores as a JPEG file inside the raw file (yes, even when you're shooting in only "RAW" mode as opposed to "RAW+JPEG" mode). Due to this fundamental fact of the data being "raw", there is no one correct way for a raw photo to look - the way your camera makes it look is not "the right way", nor is it the only way. However, many photographers would like to use the "camera look" as a starting point for further adjustments, and RawTherapee makes this possible.
When displaying a raw photo in the File Browser which has never been edited in RawTherapee before, the photo's thumbnail is based on the JPEG image embedded inside that raw file -- the exact same image you see when viewing that photo on your camera or in most other software. Once you open that photo in the Editor, RawTherapee creates a new thumbnail based on the actual raw data. Since creating an image from raw data requires "cooking" it, and since you have not manually edited that image yet, RawTherapee uses parameters from the default processing profile for raw photos to process it. From that moment on, the photo's thumbnail is no longer based on the embedded JPEG but on the actual raw data. When you make adjustments to the image in the Editor, the thumbnail is updated to reflect your changes.
Editing is done in the Editor. This is where you work with RawTherapee to create stunning works of art - or perhaps just apply first aid to your snapshots. When you open a raw photo in the Editor for the first time, the default processing profile for raw photos is applied, which as of RawTherapee 5.4 is set to "Auto-Matched Curve - ISO Low" (unless you changed it in Preferences), and it automatically adjusts your raw photo to look like the out-of-camera JPEG. It does so by analyzing the JPEG image which was created by your camera and is stored within the raw file, and adjusting the tone curve so as to match it. In most cases this match is very close to the "camera look". In rare cases it may fail. See the Auto-Matched Curve article for more information.
Take a moment to look around this Editor tab. Notice that there are tabs within this tab - on the right of screen towards the top. These tabs and the controls under them are the Toolbox. You probably have the first tab open and, if you hover your mouse over it, you'll find that it's called the Exposure tab. Below the choice of tabs are the tools the chosen tab contains – Exposure, Shadows/Highlights, Tone Mapping etc. If you click on one of them it will expand so that you can see its contents. Click again and it will collapse. Right-click on one and that one will expand while all others will collapse - a time-saving shortcut. To the left of each tool's label is a power button ( on / off) which lets you turn it on or off, or in some cases instead of a power button there is a triangular expander . Read the Tools section of the General Comments About Some Toolbox Widgets article for a detailed explanation. Browse through the tabs and panels until you feel totally overwhelmed by all that's available.
Before you start working on an image, here is some important advice – Don't Panic! You are in no danger of destroying any of your prized images if you make a mistake. RawTherapee has some features which help you protect your images:
- RawTherapee does non-destructive editing of your raw files. This means that RawTherapee will never, ever change the raw file itself. All changes are stored in sidecar files. You can find out more about them in the Sidecar Files - Processing Profiles article.
- When using the Editor, you'll see the History panel on the left. This panel shows a history stack of every change you have made to your image. To go back to any step (including when the image was first loaded), just click on the relevant line in the History panel.
- Under the History panel you'll see a Snapshots panel. You can skip it for now, but you'll find it handy when you gain experience with RawTherapee. This panel stores the state of all the tools as a "snapshot". This allows you to easily, for example, tweak your photo to a nice and colorful look and take a snapshot, then tweak it again to a lovely black-and-white look and take a snapshot, and then compare the two just by clicking on either snapshot. (Note: RawTherapee does not save snapshots to the PP3 file yet, it will do so in the future. If you have three snapshots which you want to retain, you will need to click through them and save a PP3 file each time under a unique name).
- As you might expect, Control-z will undo the previous change.
- Open the raw photo. RawTherapee automatically makes it look like your camera's output. If you're happy with the result, you're done. Else read on.
- Click on the Color tab and expanding the White Balance tool by right-clicking on it (or use the w keyboard shortcut). RawTherapee will start with the white balance used by your camera. Most white balance adjustments involve moving the Temperature and Tint sliders, or using the Spot White-Balance Picker on a colorless (neutral gray) patch. Adjust to taste.
- Next, fix the exposure by going to the Exposure tab, expanding the Exposure tool and adjusting it to taste. For now, just use the Exposure Compensation and Saturation sliders.
- If your image is noisy, switch to the Detail tab, zoom to 100% either using the button or using the z keyboard shortcut, because the effects of the tools in this tab are only visible in the zoomed-to-100% preview (and of course in the saved image), and enable the Noise Reduction tool by clicking on the power button leaving the settings at their default values for now. RawTherapee has automatically removed color (chrominance) noise. Luminance noise is removed manually, though leave it for now as luminance noise generally lends a pleasing, grainy, film-like look. As a general rule, when using noise reduction don't use sharpening. Zoom back out to see the whole image either using the button or using the f keyboard shortcut key.
- Now you decided you want to fix the geometry and composition of your photo.
- First make the horizon level, or correct the things which should be vertical such as street lamps or building edges. To easily do this, press the "s" key on your keyboard (the same as clicking the button), and click-and-drag a line along the horizon or along the edge of a building over the preview. Your image will rotate accordingly and you will automatically be taken into the Transform tab.
- To crop the photo, press the c shortcut key on your keyboard (or use the button) and click-and-drag a crop over the preview; you will notice that the Crop tool becomes automatically enabled. There is no need to "apply" a crop - it takes effect the moment you draw it. You can zoom to fit the crop area by using the f keyboard shortcut, or ⎇ Alt+f if you want to fit the whole image. You may want to set the Crop "Guide type" to "none" if it's a problem.
- Finally, you want to downscale the photo, because who wants to upload a 10MB JPEG to your social network. Enable the Resize tool and the Post-Resize Sharpening sub-tool, and leave them at the default settings. The resizing effect is only applied to the saved image, not to the preview, so you won't see any change in the preview as you enable these tools.
- You're all set, let's save it straight away. Click the Save Current Image button (located below the lower left corner of the preview area), or use the ^ Ctrl+s keyboard shortcut. Save it as a JPG file using default settings (quality at "92", subsampling at "balanced"). These are good all-round settings. Choose a folder where you want it saved to, and after a few seconds your file will be ready in the folder you selected. If you close RawTherapee, the settings you used will be stored in a PP3 sidecar file next to the raw file, so that you can re-open the raw photo in the future and retain the tool settings you used.
Now that you went through basic photo adjustment and are familiar with the steps, let's recap the steps but with more advanced details.
Always read each tool's article here on RawPedia before using it, to get a firm understanding of what it does. The articles explain how the tools work in RawTherapee, while the general concepts unspecific to RawTherapee are left to the user to find on Wikipedia or elsewhere.
Be sure to see the Keyboard Shortcuts.
The order of the tools inside RawTherapee's engine pipeline is hard-coded, so from that point of view it does not matter when you enable or disable a tool. However some tools can make a large impact on other tools, e.g. changing exposure may require you to re-adjust color toning, and some tools may require plenty of CPU power to calculate the preview making updates of the preview from then on slow, so it is for this reason we suggest you stick to this general order of operations:
- Start off by making sure that RawTherapee's environment is set up correctly, meaning:
- Make sure that RawTherapee is using your monitor's color profile if you use a color-managed workflow. Check Preferences > Color Management. You may also need to load the appropriate calibration curves into your graphics card if you built your monitor color profile on top of them, though how you do that is outside the scope of RawTherapee.
- Make sure that the Color Management tool is configured correctly. Usually the defaults are best. Read the Color Management and Color Management addon articles. If instead of using the color matrix or DCP or ICC profiles shipped with RawTherapee you decide to use an external one, for example a self-made DCP or one from Adobe, load it as the first thing you do, otherwise you may need to re-adjust some of the color tools. Always use an output profile - in most cases the default one, RT_sRGB. If you think you're being smart by selecting "No ICM: sRGB Output", you're mistaken.
- If you want to use a Flat-Field and/or Dark-Frame image, do so now, to avoid re-adjustment.
- Now set the correct White Balance. You may fix the exposure first if the image is too dark (or too bright) to see white balance changes.
- Next, adjust the Exposure, using the Exposure Compensation and Black sliders to get the image into the right ballpark. Once in the right ballpark, continue with using both tone curves. Be sure to read the Tone Curve section in the Exposure article to learn why there are two of them and how best to use them - they are a very powerful tool!
- In the Basics section above we suggested that you use the Saturation slider (in the Exposure tool). Now that you've learned the basics and are exploring more advanced techniques, we suggest you not use the Saturation slider anymore, and instead use the more powerful CC curve in the Lab Adjustments tool, as it gives you finer control.
- The order of the rest gets fuzzy. Some tools will unavoidably influence others. Carry on with the Lab Adjustments tool and then the rest of the tools in the Exposure tab.
- Then use the tools in the Color tab.
- Then zoom to 100% and use the tools in the Detail tab. Generally, don't sharpen if you're using noise reduction.
- Finally, zoom out again and use the tools in the Transform tab. The reason you left these for last is that they may make the preview image appear a bit blurry, because in order for the preview to be responsive, RawTherapee uses that very preview image you see at the very resolution you see - small - to show what the tools do, and when you rotate or otherwise change the geometry of a small image, there is a clear softening. This is not a problem when saving as by that point RawTherapee does its processing on the full-sized image, which is slow but of high quality.
- You can edit metadata in the Meta tab at any time before saving.
- Save, either directly when you want to save a single photo, or via the Batch Queue when you want to process many photos. See the Saving Images article.