Show HN：完全本地运行、免费开源的 Adobe Lightroom 替代品 Rembrandt，集成 AI 功能

用文字提出要求：输入“warmer and a bit brighter”“down exposure by ten points”“shadows +25”或“paste the edits from the previous photo”（Ctrl/⌘ K）。一个由点阵构成的小 Rembrandt 会思考片刻，然后在你看到滑块移动的同时完成每一项调整。它运行在你的设备上：使用的是词汇系统，而非语言模型。

直接编辑照片：在图片任意位置上下拖动，可提亮或压暗该区域的色调；左右拖动可改变对应颜色；滑块会同步跟随。

AI 风格效果：Enhance、Relight、Sky、Atmosphere、Sunrays、Skin、Motion 和带光圈形状的 Lens Blur，基于设备本地的深度图和主体图生成。

重新对焦：为失焦照片恢复细节，即使是严重失焦也可以处理（GPU 上的正则化反卷积）；可处理主体或整张图片。

超级分辨率：提供具备真实细节的 2× 和 4×放大；对于偏软的照片，可在原始尺寸下使用 Restore；在 GPU 上运行（Apple silicon 使用 Metal）。

AI 降噪：将高 ISO 照片清理为新的 DNG 文件，并保留相同的编辑效果；在 GPU 上运行。

不打扰你的后台任务：AI Denoise、Super Resolution 和合并任务会以小型 GPU 时间片运行，在你编辑时暂停，也可在你离开时或你设定的夜间时段运行（设置 › 性能）。队列可在重启后保留。

合并：可将包围曝光照片合成为 HDR，将照片合成为全景图或焦点堆叠图；每种结果均输出为类似 RAW 的 DNG。

RAW：支持超过 1,000 款相机的 RAW 文件，并通过 GPU 处理：色调、颜色、曲线、分级、去朦胧、细节。

蒙版：画笔、渐变、颜色与色调范围，以及 AI 主体、背景、对象和深度蒙版。

移除：修复和仿制污点及笔划；Rembrandt 会自动为你选择匹配的源区域。

镜头校正：支持 Fujifilm 和 Sony RAW 文件中相机内置的配置文件，或 Lensfun 提供的 1,500 个镜头配置文件（畸变、暗角、色差）；还可针对任意照片手动调整畸变和暗角。可自动拉直水平线和地平线。

设备端 AI：重新对焦、背景替换。不会上传任何内容。

图库：相册、评分、旗标、颜色标签、关键词、虚拟副本、搜索、查找相似照片、排序、键盘快捷键（也可使用 Lightroom 快捷键）、支持撤销的一键删除。

批处理：可将编辑内容复制并粘贴到数百张照片，支持批量导出，以及适配各照片曝光情况的预设。可监视一个文件夹，并在新照片到达时自动应用预设和相册。

分享方式：可生成带滑块的调整前后对比页面、编辑过程回放视频，或将编辑配方嵌入导出的文件中，让任何人都能查看（并复用）其编辑方式。

导入照片：支持文件夹、Lightroom Classic（编辑、关键词、标签、虚拟副本、收藏集，并会报告无法导入的内容），以及 Lightroom、Google Photos、Google Drive、Dropbox、OneDrive（设置说明）。也可以再导出回这些服务。

开放格式：编辑记录采用标准 XMP 格式，Lightroom 和其他软件均可读取。导出文件会保留相机信息和拍摄日期，添加你的姓名与版权信息，并嵌入 sRGB 配置文件；不会写入位置信息。

云同步（可选、付费）：可在设置中启用，以在你的电脑、Web 端和手机之间同步编辑记录、相册和照片。这是唯一需要账户、也是唯一收费的功能；其余所有功能均保持免费。

Lightroom：日常编辑和图库管理所需的功能已基本具备：RAW 处理、蒙版（包括 AI 主体、深度和对象）、修复、预设、镜头校正、HDR 和全景合并、降噪、批量编辑和目录导入。暂未提供：打印、图书、幻灯片、Web 和地图模块、人脸识别、Adobe 的相机配置文件、联机拍摄（监视文件夹可覆盖大部分联机拍摄应用），以及插件生态系统。

darktable：Rembrandt 借鉴了 darktable 的核心理念，即 scene-referred（场景参照）处理管线——编辑在线性光空间中进行，之后再通过色调曲线映射到屏幕，因此高光能够干净地恢复。darktable 拥有更多模块和更细致的控制；Rembrandt 的目标是在五分钟内即可上手，提供更少但覆盖范围更广的控制项，以及设备端 AI。其引擎为独立实现（见致谢）。

RawTherapee / ART：与 darktable 覆盖相似领域；Rembrandt 以控制深度换取更易用的操作体验。

GIMP / Photoshop：属于不同类型的工具。它们是用于合成和绘制的像素编辑器；Rembrandt 则是类似 Lightroom 的非破坏性 RAW 开发与图库工具。

Ask in words : type “warmer and a bit brighter”, “down exposure by ten points”, “shadows +25” or “paste the edits from the previous photo” (Ctrl/⌘ K). A small Rembrandt in dots thinks it over, then makes each change while you watch the sliders move. It runs on your device: a vocabulary, not a language model.

Edit the photo itself : drag up or down on any part of the picture to lighten or darken that tone, left or right to change that colour; the sliders follow.

AI looks : Enhance, Relight, Sky, Atmosphere, Sunrays, Skin, Motion and Lens Blur with aperture shapes, from on-device depth and subject maps.

Refocus : brings back detail in out-of-focus photos, even heavy defocus (regularised deconvolution on the GPU), on the subject or the whole picture.

Super Resolution : 2× and 4× with real detail, or Restore at the same size for soft photos; runs on the GPU (Metal on Apple silicon).

AI Denoise : clean high-ISO shots into a new DNG with the same edits, on the GPU.

Background work that stays out of the way : AI Denoise, Super Resolution and merges run in small GPU slices that pause while you edit, or when you're away, or overnight in a night window you set (Settings › Performance). The queue survives restarts.

Merge : HDR from brackets, panoramas and focus stacks, each to a RAW-like DNG.

RAW from 1,000+ cameras, developed on the GPU: tone, colour, curves, grading, dehaze, detail.

Masks : brush, gradients, colour and tone ranges, AI subject, background, object and depth.

Remove : heal and clone spots and strokes; Rembrandt picks a matching source for you.

Lens corrections : the camera's built-in profile from Fujifilm and Sony RAWs, or one of 1,500 lens profiles from Lensfun (distortion, vignetting, chromatic aberration), plus manual distortion and vignetting for any photo. Auto straighten levels horizons.

On-device AI : Refocus, background replacement. Nothing is uploaded.

Library : albums, ratings, flags, colour labels, keywords, virtual copies, search, Find similar, sorting, keyboard shortcuts (or Lightroom's), one-click delete with Undo.

Batch : copy and paste edits to hundreds of photos, batch export, and presets that fit each photo's exposure. Watch a folder to apply a preset and album to new photos as they arrive.

Share how : a before/after page with a slider, a replay video of the edit, or the recipe inside the exported file so anyone can see (and reuse) how it was edited.

Bring your photos : folders, Lightroom Classic (edits, keywords, labels, virtual copies, collections, with a report of anything that can't come over) and Lightroom, Google Photos, Google Drive, Dropbox, OneDrive (setup). Export back to them too.

Open formats : edits are standard XMP, readable by Lightroom and others. Exports keep the camera details and date taken, add your name and copyright, and embed an sRGB profile; location is never written.

Cloud sync (optional, paid) : turn it on in Settings to sync edits, albums and photos between your computers, the web and your phone. It's the only thing that needs an account, and the only thing that costs money; everything else stays free.

Lightroom : the everyday editing and library work is here: RAW development, masks (including AI subject, depth and object), healing, presets, lens corrections, HDR and panorama merges, denoise, batch editing, and catalog import. Not here yet: Print, Book, Slideshow, Web and Map modules, face recognition, Adobe's camera profiles, tethered capture (a watched folder covers most tethering apps), and a plugin ecosystem.

darktable : Rembrandt borrows darktable's central idea, a scene-referred pipeline (edits work on linear light before a tone curve maps it to the screen), which is why highlights recover cleanly. darktable has far more modules and control; Rembrandt aims to be usable in five minutes, with fewer, broader controls and on-device AI. The engine is an independent implementation (see Credits).

RawTherapee / ART : similar ground to darktable; Rembrandt trades depth of control for speed of use.

GIMP / Photoshop : different kind of tool. Those are pixel editors for compositing and painting; Rembrandt is a non-destructive RAW developer and library, like Lightroom.