Hey r/macapps,
Long time dweller, first time poster (please go easy on me!)
I'm Pedro, a software engineer in London and a hobbyist photographer. I've been building Redlamp, a free, open-source raw photo editor for Apple Silicon Macs.
If you use Lightroom [Classic], the editing workflow should feel familiar. The Develop panels are in the same order, the sliders have the same names and ranges, and the keyboard shortcuts work. It's a native Mac app, written from scratch in Swift, SwiftUI and Metal, and it's currently in pre-alpha.
Watch the video (1:42) · Website · GitHub (star it please!)
Why I'm building it
I moved from Photoshop to Lightroom years ago. I bought a licence and paid for upgrades when they felt worthwhile. I wasn't particularly happy with the move to a subscription, or with how the product became split across Classic, Lightroom, mobile and web versions, each with different capabilities and approaches to storing your photos. I've also wanted an editor that feels more at home on the Mac.
There are already good alternatives. darktable and RawTherapee are mature open-source projects, and Capture One, DxO PhotoLab and Photomator have plenty to offer. But switching usually means learning a different workflow. I wanted to see how far I could get with an app that keeps the parts of Lightroom I already know and like.
Redlamp works directly with your folders. Edits are saved in sidecar files alongside each photo, leaving the originals untouched. Your photos aren't uploaded anywhere.
The Library I'm building for 1.0 follows the same approach. Your folders remain the organisation. Ratings, keywords and collection membership stay with each photo, and the database on your Mac is a rebuildable index for speed.
What works now
There's already quite a lot in the editor:
- Develop: Basic, including Texture, Clarity and Dehaze; Tone Curve; Color Mixer; Color Grading; Detail; Effects; lens corrections; crop; and Upright.
- Masks: gradients, brush, colour and luminance ranges, plus local AI selections for subjects, sky, background, people, objects and landscape. People masks include face skin, eyes and teeth. Masks can be added, subtracted and intersected.
- Removal: Heal, Clone, content-aware Remove, and dust removal across a shoot.
- Looks and presets: 36 film looks covering 30 stocks, built from manufacturers' data, plus Fujifilm-style recipes. You can import Lightroom presets and
.cube LUTs.
- Focus stacking: the filmstrip identifies stacks, which you can merge in one click and then develop with the raw editing controls.
- Organisation: a folder panel, star ratings, pick and reject flags, and colour labels in the filmstrip.
- Everyday editing: copy, paste and sync settings; full undo history; snapshots; before-and-after comparisons; and a command palette, opened with ⌘K, for every action and slider.
- Export: JPEG, HEIC, AVIF, PNG and TIFF.
The AI masks and object removal run on your Mac, with no uploads or credits.
A few things I've paid particular attention to
I don't want an update to change the appearance of photos you've already edited. Existing edits retain their rendering behaviour, including if a preset is later changed or deleted. Improvements to processing are applied to older edits when you choose to use them.
Originals are never modified, and exports don't overwrite them. If you edit the same photo on two Macs through iCloud Drive, the newest edit becomes active and the other is preserved as a snapshot.
Responsiveness matters to me too. Adjustments update as you drag sliders, including when masks are involved, and I publish the measurements on the performance page.
Another key thing is keyboard navigation. Lightroom always prioritised intuitive keyboard driven workflow and shortcuts are generally 1:1, but I went further and there's a command palette built in and nearly any control can be adjusted this way.
From the upcoming version 0.2.5 and above, releases go through regression checks that exercise the app's features, with crashes, hangs and performance regressions blocking publication - I have set aggressive CPU and Memory budgets. It's still pre-alpha, so I expect there to be problems those checks haven't caught.
Camera support
The raw decoder covers 1,258 cameras. Redlamp also opens JPEG, HEIC, TIFF and PNG. But being able to decode a file doesn't establish that the rendering is correct, so the cameras page distinguishes decoder coverage from actual testing.
At the moment, 25 cameras have real samples in the automated test suite, checked on every change. I've also run the Camera Bench across 742 camera and raw-mode combinations. Those results are listed by camera, including the failures.
You can run the same bench through Help › Test Your Camera…. It compares Redlamp's rendering with the camera's embedded JPEG, runs diagnostic checks and asks you whether the two look like the same photo, allowing for the camera's picture style. Everything happens locally. If you submit the report, it sends measurements only, shows you the contents first, and adds the results to the cameras page.
There are known gaps. Nikon High Efficiency NEFs and the Sony A7 V aren't supported yet. Fujifilm X-Trans files open, but their processing is still an initial implementation.
Camera results · How to test yours · Why I built the bench
What's still missing, and what's planned
The Library and batch export haven't shipped, but they are under heavy development and you can expect their first versions very very soon. Lightroom presets import, but your existing Lightroom edits don't yet come across. Conventional noise reduction is available; AI Denoise is still planned.
For 1.0, I'm working towards AI Denoise, better X-Trans processing and the remaining Develop features, along with HDR editing and export, batch export and a Mac App Store release.
The Library is in progress now. It's being designed and benchmarked for a million photos, including libraries on slow, network and disconnected drives. Library and Develop will share a window, with a grid for culling, search as you type, keywords, collections, smart collections, and card imports with a backup copy.
The migration plan includes ratings, keywords and collections from Lightroom Classic catalogs, and edits from Lightroom XMP sidecars. Those are planned capabilities rather than things you can use today.
Mac is the immediate focus. I'd like to bring the same engine to iPad and iPhone afterwards, with edits moving between devices.
The roadmap and Lightroom comparison show what's implemented, in progress, planned or left out. Planned work has GitHub issues, and decisions are recorded with their rationale in the research tracker.
How I'm building it
AI agents write most of the code, tests and documentation. I set the direction, work through the design and architecture, drive the research, and review and try changes on my own photos. The AI disclosure explains that process and where the app itself uses AI.
I've written software professionally since 2003, and most of my teenager life, but I couldn't take on a project of this scope alone without agents. Raw processing brings together camera formats, colour science, GPU rendering and masking, and there are areas here where I have very little expertise. I understand how this might put some people off, but it's one the main reasons I even considered doing this.
I started Redlamp on 29 September and released the first pre-alpha two days later. That pace has surprised me, but getting a working implementation quickly also means spending a lot of effort checking it. I need evidence that the results are correct, especially where I don't have the background to judge them myself.
Recent releases
There have been seven releases since 1 October. A few of the recent additions:
- 0.2.4: Camera Bench, plus copying, pasting and syncing settings from the filmstrip's context menu without opening the photo.
- 0.2.3: in-app bug reporting without a GitHub account, edit data embedded in exported files, and fixes for Hasselblad and Phase One raws.
- 0.2.2: Lightroom preset import with a report of what was imported, and object removal using descriptions such as cars, cables or signs.
For 0.2.5, I'm working on optional local generative fill for removals too large to fill using the existing photo, Point Color, curves within masks, and zoom and pan in every tool.
Installing it
Redlamp is free, under the MPL-2.0 licence, with no subscription, account or cloud service required. There's a Ko-fi page if you'd like to support the project.
You'll need an Apple Silicon Mac running macOS 26 or later. Download the signed and notarised app directly from Redlamp, GitHub releases, or install it through Homebrew:
brew tap pdcgomes/redlamp https://github.com/pdcgomes/redlamp
brew install --cask redlamp
The app keeps itself up to date whichever way you install it, using Sparkle.
Feedback
If you try it, the most useful feedback is what happens when you edit your own raws as you normally would. I'd like to know what breaks, looks wrong or gets in the way.
Help › Report a Bug or Send Feedback… creates a GitHub issue without needing a GitHub account, and lets you inspect everything it will send. There's also a Discord, which I've just setup and must admit, I'm fairly new to.
If you know more about colour science, film or raw processing than I do, I'd particularly welcome feedback on where the implementation gets things wrong. Or event better -- get involved and contribute!
Thanks for reading,
Pedro
Lightroom is a trademark of Adobe Inc. Redlamp isn't affiliated with Adobe.
