A LUT that will not load is usually a LUT in the wrong format. The colourist sent a .3dl, the camera vendor ships a .look, the app you use only takes 3D .cube files, or the file is a 1D curve where a 3D table is expected. A LUT converter fixes that by reading one format and writing another.
Why does a LUT need converting?
LUTs come in many formats, and each app reads only some of them:
| Format | Where it comes from | Notes |
|---|---|---|
.cube (3D) | Adobe specification, used almost everywhere | The format most apps expect |
.cube (1D) | Same format, a curve per channel | Some apps reject it |
.3dl | Autodesk and some older systems | Integer values, different layout |
.look, .lut, .csp, .mga | Various grading systems | App-specific |
| HALD image | A PNG with colours arranged in a grid | Used to capture a preset as a LUT |
If the app says the file is invalid, it is often a valid LUT in a format the app does not read. What is a .cube file explains what a 3D .cube contains.
Which LUT converter should you use on a Mac?
| Tool | What it converts | Good for |
|---|---|---|
| Lattice | Reads and writes many formats, including .cube and Autodesk .3dl; resizes and combines LUTs | Most conversions, on a Mac |
| DaVinci Resolve (free) | Applies any LUT it can read as a grade, then exports a .cube | When Resolve reads the source file |
| A HALD workflow | A preset applied to a HALD image, turned into a .cube | Converting a photo preset into a LUT |
| Command-line tools | Scripts and libraries such as OpenColorIO | Pipelines and automation |
Lattice is the dedicated tool. Its App Store listing describes reading and writing DaVinci Resolve 1D and 3D .cube and Autodesk 3D .3dl among many others, plus resizing a LUT and merging several into one. If a LUT will not load anywhere, Lattice is also where you find out why.
DaVinci Resolve works as a free converter for formats it can read: apply the LUT to a clip, then generate a LUT from that grade and save it as .cube.
For a Lightroom preset, there is no file to convert; you capture the preset with a HALD image. Lightroom preset to LUT walks through it.
How do you convert a LUT to .cube, step by step?
- Identify the source. Look at the extension, and for a
.cube, open it in TextEdit and check whether it saysLUT_1D_SIZEorLUT_3D_SIZE. - Open it in the converter. In Lattice, open the file; in Resolve, apply it to a clip on the colour page.
- Choose the output. 3D
.cube, size 33 for most looks, 65 for precise technical conversions. - Check the input range. Most LUTs expect 0 to 1 input. A LUT built for a different range, such as one from a system that uses integer values, must be scaled correctly or the result shifts.
- Export.
- Test it. Apply the original and the converted LUT to the same test image and compare. They should match.
Step 6 is the one people skip. A conversion with the wrong range looks almost right, which is worse than obviously wrong.
How do you convert a 1D LUT to a 3D LUT?
A 1D LUT adjusts red, green and blue independently, so it can express contrast and colour balance, but not cross-channel changes. Any 3D LUT can represent a 1D LUT exactly, so converting in that direction loses nothing. Lattice does it directly, and Resolve does it by applying the 1D LUT and exporting a 3D one.
Going from 3D to 1D does lose information, and is rarely needed.
What size should the converted LUT be?
| Size | When to use it |
|---|---|
| 17 | Small files, some hardware monitors; may band on smooth gradients |
| 33 | The common default for creative looks |
| 65 | Technical conversions, where precision matters |
Upsizing a LUT does not add detail that was not there; it only resamples the same curve. Keep the source size unless an app demands another.
What do you do with the converted LUT?
Use it. For a whole shoot, BatchTone applies a 3D .cube to a folder of photos and video at once, on a Mac:
- Import the converted
.cubeonce; it stays in the library. - Drop the folder in, photos and clips mixed. Each look is previewed on your own first frame.
- Set a strength per file where the look is too much.
- Export JPEG, PNG or H.264 MP4 to a folder you choose. Originals are never modified, and nothing is uploaded.
BatchTone reads 3D .cube files of any size and repairs malformed DJI headers on import. It does not read 1D LUTs, .3dl or other formats, which is exactly why the conversion above comes 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
Common questions
Is there a free LUT converter?
DaVinci Resolve's free version can export a .cube from any LUT it can read. Lattice is paid software on the Mac App Store.
Can I convert a LUT online?
Some websites convert LUT formats in the browser. Check the result on a test image either way, and avoid uploading LUTs you bought under a licence that forbids sharing them.
Can I convert a .cube to a Lightroom preset?
Not to a preset, but Lightroom can use a LUT through a profile. LUTs in Lightroom shows how.
Why does my converted LUT look different?
Usually the input range, or the source was built for a different colour space. Compare both on the same test image and check the converter's range settings.