# What is a .cube file? Opening and using one > A .cube file is a colour LUT stored as plain text. What is inside it, which apps open it on a Mac, why some refuse to load, and how to apply one to photos and video. Canonical: https://batchtone.com/blog/cube-file 20 October 2026 · 4 min read A .cube file is a LUT (lookup table) saved as plain text: a list of numbers that tells software how to change every colour in an image. You do not open it like a document; you load it into a photo or video app such as DaVinci Resolve, Final Cut Pro, Premiere Pro, Photoshop or a LUT tool, and the app applies it to your footage or photos. You bought a LUT pack, or downloaded your camera's official conversion, and the folder is full of files ending in `.cube`. Double-click one and your Mac either asks which app to use or opens a wall of numbers in a text editor. Both are normal. A `.cube` file is not an image or a preset; it is a colour recipe that another app reads. ## What is a .cube file? It is the most common file format for a **LUT**, a lookup table. A LUT says: for this input colour, output that colour. Load one into an app and every pixel of your photo or clip is remapped by it. That is how one file can turn grey log footage into normal contrast, or give a whole shoot a film-like palette. [What is a LUT](https://batchtone.com/blog/what-is-a-lut) explains the idea in five minutes. Its specification is published by Adobe, and it is read by almost every grading, editing and photo app that supports LUTs, which is why most packs ship as `.cube`. ## What is inside a .cube file? Open one in TextEdit and you see something like this: ``` TITLE "Warm Film" LUT_3D_SIZE 33 DOMAIN_MIN 0.0 0.0 0.0 DOMAIN_MAX 1.0 1.0 1.0 0.0012 0.0008 0.0000 0.0345 0.0011 0.0002 ... ``` | Line | What it means | |---|---| | `TITLE` | An optional name | | `LUT_3D_SIZE 33` | A 3D LUT with a 33 × 33 × 33 grid of sample points | | `LUT_1D_SIZE` | Used instead for a 1D LUT, which adjusts each channel separately | | `DOMAIN_MIN` / `DOMAIN_MAX` | The input range, usually 0 to 1 | | Rows of three numbers | The output red, green and blue for each grid point | A size-33 LUT has 35,937 rows; a size-65 one has over 270,000. Bigger grids are more precise and larger files. Colours between grid points are interpolated, so 33 is plenty for most looks. ## How do you open a .cube file on a Mac? You load it into an app, rather than opening it on its own: | App | Where a .cube goes | |---|---| | DaVinci Resolve | A node on the colour page, or the LUT folder | | Final Cut Pro | The Custom LUT effect | | Premiere Pro | Lumetri Color, Input LUT or Creative Look | | Photoshop | A Color Lookup adjustment layer | | Pixelmator Pro, Affinity Photo | Their LUT adjustments | | Lightroom | Not directly; it has to become a profile first | [How to install LUTs](https://batchtone.com/blog/how-to-install-luts) shows the exact steps for each. To simply preview a pack, a LUT viewer app shows each look on a sample image. ## Why won't my .cube file load? Four usual causes: - **It is a 1D LUT.** Some apps only accept 3D LUTs. The file will say `LUT_1D_SIZE` near the top. - **The header has a stray character.** Some DJI files use a tab instead of a space after `LUT_3D_SIZE`, and strict readers such as ffmpeg reject them. - **The size is unusual.** A few apps limit the grid size they accept. - **It is not really a .cube.** A `.3dl`, `.look` or `.csp` file renamed to `.cube` will not load. Those need converting; [LUT converter](https://batchtone.com/blog/lut-converter) covers how. ## Is a .cube file the same as a preset? No. A preset stores slider positions for one app. A `.cube` stores the colour result and works across apps, but it cannot store crops, sharpening or local edits. [LUT vs preset](https://batchtone.com/blog/lut-vs-preset) compares them. ## How do you apply a .cube file to many files at once? Most apps apply a LUT one photo or one clip at a time. For a whole folder, BatchTone does it on a Mac: 1. Drop a folder of photos and clips in, mixed. 2. Import your `.cube` files once; they stay in the library, each previewed on your own first frame. 3. Set a strength per file for the ones that need less. 4. Export JPEG, PNG or H.264 MP4 to a folder you choose. Originals are never modified, and nothing is uploaded. It reads standard 3D `.cube` files of any size, and repairs the malformed DJI ones on import. It does not read 1D LUTs or other formats such as `.3dl`, so convert those first. Only your own files and LUT pack can show whether it fits, which is why the seven-day trial has everything unlocked: video, unlimited batches, no watermark. After that it is one in-app purchase, not a subscription. [Download BatchTone free on the Mac App Store](https://batchtone.com/download) ## Common questions ### Is a .cube file safe to open? Yes. It is plain text holding numbers, with no code in it. Opening it in a text editor does nothing harmful. ### Can I open a .cube file on an iPhone? Some iPhone photo and video apps can import a `.cube`. The file itself does nothing without an app that applies it. ### Which .cube size should I use? Size 33 is the common default and enough for most looks. For precise technical conversions, 65 is used. A 17 grid is small and can band on smooth gradients. ### Can I edit a .cube file? You can edit the text, but changing numbers by hand is not a practical way to change a look. Change the grade in an app and export a new LUT; [how to create a LUT](https://batchtone.com/blog/how-to-make-a-lut) shows four ways. **About this article.** Written by the team that builds BatchTone, a macOS app that applies .cube LUTs to whole folders of photos and video. Spotted something wrong or out of date? Write to [support@batchtone.com](mailto:support@batchtone.com). ## Read next Explainers 19 September 2026 · 4 min read ## [What is a LUT? The whole idea in five minutes](https://batchtone.com/blog/what-is-a-lut) LUT stands for lookup table. In video and photo editing, a LUT is a file that says, for a grid of input colours, what each one should come out as. Applying a LUT means looking up every pixel in that grid and interpolating between the nearest entries. [Read it](https://batchtone.com/blog/what-is-a-lut) How-to 9 October 2026 · 6 min read ## [How to install LUTs: Resolve, Premiere, Final Cut and more](https://batchtone.com/blog/how-to-install-luts) To install a LUT, unzip the pack and either copy the .cube files into the app's LUT folder or load them through the app's own browse button. Resolve and Premiere list LUTs from a folder; Final Cut, After Effects, CapCut and Photoshop load a file when you pick it; Lightroom needs the LUT turned into a profile first. [Read it](https://batchtone.com/blog/how-to-install-luts) How-to 20 October 2026 · 5 min read ## [LUT converter: turning .3dl, .look and 1D LUTs into .cube](https://batchtone.com/blog/lut-converter) To convert a LUT to .cube on a Mac, load it into a LUT utility such as Lattice and export it as a 3D .cube, or load it in DaVinci Resolve as a grade and export a new .cube from there. Check the converted file on a test image against the original before you rely on it, because a wrong input range or size changes the result. [Read it](https://batchtone.com/blog/lut-converter) ## One look. A whole shoot. BatchTone applies your .cube LUTs across photos and video at once, with a strength dial on every file. Seven-day trial, everything unlocked. [Download for macOS](https://apps.apple.com/app/batchtone/id6821727167)