Free photo editing for spotters: darktable, RawTherapee and GIMP

You come back from the fence with 1,500 burst frames, three of them really good – and then your photo editor asks you for a monthly subscription. It doesn’t have to be that way. With darktable, RawTherapee and GIMP, there are three mature, free programs that get your aircraft photos to upload level. This guide shows you what each program can do, where it falls short and how to combine the three into a spotter workflow that runs from RAW to the finished picture.

The short answer

If you only want to install one program, take darktable: It manages your images, develops RAW files non-destructively and exports whole series in one go. RawTherapee is the complement for individual images where the finest details matter. You only need GIMP when you want to retouch something out of the picture or combine layers. All three are free software with no subscription and run on Windows, macOS and Linux.

The difference between the program types is important. A RAW developer works with the camera’s raw data and stores only recipes, not altered pixels. A pixel editor like GIMP changes the image itself, layer by layer. For aircraft photos, where bright fuselages, dark engine intakes and sky come together in one picture, the RAW developer is the more important tool. Why RAW is worth it at the fence is explained in the article RAW or JPEG for plane spotting?.

The three programs at a glance

Criterion	darktable	RawTherapee	GIMP
Program type	RAW developer with image management	pure RAW developer	pixel editor with layers
RAW files	directly	directly	only via darktable or RawTherapee as a plug-in
Image management	library with ratings, color labels, tags	file browser, no database	none
Stores edits	database plus XMP sidecar file	sidecar file per image	in the image file or the XCF project
Batch processing	copy settings, batch export	copy settings, processing queue	only via scripts or plug-ins
Strength for spotters	complete workflow in one program	detail quality for individual images	retouching, layers, composites
Learning curve	medium to steep	medium	medium

As of October 2026, darktable 5.6, RawTherapee 5.13 and GIMP 3.2 are the current version lines. The programs are under continuous development, so it’s worth checking the official sites before downloading.

darktable: the all-rounder for your spotter archive

darktable is the closest thing to a classic subscription program for photographers. You import your shots into the library, sort them in the lighttable and develop them in the darkroom. The program opens RAW files read-only. Every edit lands in a database and additionally in an XMP sidecar file right next to the original. If you want to edit an image twice, say once in color and once in black and white, each variant gets its own sidecar file.

What makes darktable strong for aircraft photos

• Series under control: You edit the best image of a landing and copy the settings to the rest of the series. After that you only adjust small things. For spotting sessions with hundreds of shots, this saves an enormous amount of time. More tricks on this are collected in the guide Editing burst series efficiently.
• Rating and culling: Stars, color labels and rejecting at the press of a key – fast culling works right in the lighttable. How to go about it is covered in the guide Culling photos quickly.
• Tags and metadata: You can assign registration, airline and airport as keywords and filter by them later. More on this in the article Metadata for aircraft photos.
• High dynamic range: darktable calculates internally with floating-point values. Bright fuselages in harsh sun and dark undersides can therefore be balanced with plenty of headroom.
• Use the graphics card: Computationally intensive modules run via OpenCL on the graphics card, if it is supported.

AI denoising in darktable

With version 5.6, released in June 2026, darktable gained an optional AI module. It can denoise RAW files, and denoise and upscale developed images. The module is off by default and is activated in the preferences; darktable then downloads the models separately. For RAW denoising, darktable creates a new DNG file that is automatically imported back into the library. For night shots or gloomy winter days at high ISO, that is a real enrichment. When AI denoising is worthwhile in general is described in the article Noise reduction with AI denoise.

Where darktable is demanding

The interface is powerful but confusing at first. Many functions exist in several modules, and the terms differ from what you may know from other programs. Plan on a few evenings until you’ve found your standard modules. Helpful: Hide all the modules you don’t need, and set up your own module group with the five or six tools you use on every aircraft picture.

RawTherapee: the specialist for detail work

RawTherapee is a pure RAW developer. There is no library in the sense of a database, but a file browser that accesses your folders directly. The program stores an image’s settings in a small sidecar file next to the original. That makes RawTherapee light and transparent: You can keep your folder structure as it is, for example following the scheme from the guide Archiving aircraft photos.

What makes RawTherapee strong for aircraft photos

• Many demosaicing methods: How a color image is made from the sensor data, you can choose yourself in RawTherapee. According to the developers, you can even combine two methods in one image. For fine details such as registrations, rivets or antennas on the fuselage, this can bring visibly cleaner edges.
• Fine sharpening and noise controls: The tools for sharpening and noise reduction are very detailed. If you like to understand what a slider does, you’ll find plenty of control here.
• 32-bit floating-point processing: The engine calculates with high precision, which avoids tonal banding in the sky with strong corrections.
• Queue: You send fully adjusted images into a processing queue and export them in a batch while you work on the next image.

Where RawTherapee reaches its limits

For a large archive with search by registration or airline, RawTherapee lacks the database. Local corrections, that is, selectively brightening an engine or darkening a patch of sky, are also less comfortable than in darktable. Many spotters therefore don’t use RawTherapee as their main program but for the ten best images of a season – for prints, for example, as described in the guide Printing aircraft photos.

GIMP: retouching and final polish at the end

GIMP is not a RAW developer but a classic image editor with layers, masks and selection tools. With GIMP 3.0, released on March 16, 2025, the program made a big leap after seven years of development: Most common filters now work non-destructively. They stay attached to the layer after being applied and can be reopened, switched off or deleted later. GIMP 3 also keeps color spaces beyond sRGB instead of converting everything internally.

For RAW files, GIMP falls back on the other two programs. Since version 2.10, darktable or RawTherapee can serve as a plug-in: You open the RAW file in GIMP, develop it in the RAW program and get the result back in GIMP. In practice, though, it is usually easier to export a 16-bit TIFF from the RAW developer and open that in GIMP.

Typical GIMP tasks for spotters

• Sensor spots in the sky: With the Healing tool, dust specks that stand out against blue sky at small apertures disappear. How to find them reliably is shown in Finding and removing sensor spots in the sky.
• Distracting elements: A fence wire at the edge of the frame, a light pole behind the vertical stabilizer – cloning and healing can remove such remnants. Caution: Many upload portals reject visible manipulation of the aircraft.
• Layers and composites: For collages, time-lapse images or composites of several shots, GIMP is the right tool.

A spotter workflow with free software

The programs play to their strengths best in combination. The following process works with darktable as the hub, with RawTherapee and GIMP stepping in as needed.

Two deep dives are worthwhile for step 3: How to correct color casts from haze or evening light is covered in the guide Correcting white balance and colors. How to set the crop so the aircraft sits cleanly in the frame is explained in Cropping and straightening aircraft photos properly. The basics of the controls themselves are covered in the article Editing aircraft photos.

Sharpening and export for portals

Sharpening comes last, matched to the output size. An image that looks good at full resolution often looks soft after downsizing to portal size. Both RAW developers offer resizing on export, after which you can sharpen selectively. How to do that without halos on fuselage edges is shown in Sharpening aircraft photos without artifacts. The right pixel dimensions and file formats for Instagram, forums and websites are under Export settings for aircraft photos. If you want to upload to JetPhotos, mind the criteria from Editing photos for JetPhotos and others – there, cloning work on the aircraft is a common reason for rejection.

Which program suits you?

What to keep in mind

• Don’t learn three programs at once. Start with one RAW developer and work only with it for a few weeks. If you keep switching, you won’t learn any of them properly.
• Monitor first. The best software helps little if your screen distorts colors. For tips, see Calibrating your monitor.
• Keep master files. Always export a copy for portals and leave the full resolution in the archive.
• Be careful with retouching. Remove dust and distractions at the edge of the frame, but no parts of the aircraft, registrations or antennas. Documentary spotter photos live on their authenticity.
• Use official downloads. Download the programs from the project sites or from trustworthy package sources, not from download portals with their own installers.

If you’re facing the subscription question right now, you can also compare the free programs with the paid alternatives: The article Capture One, Lightroom and DxO compared shows what the commercial solutions offer in addition. And if you edit on your phone on the go, you’ll find help under Editing aircraft photos on a smartphone.

Conclusion

For aircraft photos at a high level, you don’t need a subscription. As the all-rounder, darktable covers the complete path from import to export and with version 5.6 even brings optional AI denoising. RawTherapee gets a lot of detail out of individual shots, and GIMP takes over retouching when dust or fence remnants get in the way. The programs are more demanding than some paid software but reward the learning effort with full control over your images – and with an archive that doesn’t depend on a license.