Export or download LUTs for long enough and you will see the same look offered as a 33 and a 65 version. Is bigger always better? Short answer: for typical log-to-Rec.709 conversions and grading looks, 33 is enough. 65 earns its keep for display calibration and LUTs with sharp color transitions.
1. What the grid size means
A 3D LUT divides the R, G and B axes into evenly spaced points and stores an output color for each grid point. Colors between points are calculated by interpolation from their neighbors.
| Grid | Grid points | Approx. .cube size |
|---|---|---|
| 17 | 4,913 | ~0.1 MB |
| 33 | 35,937 | ~1 MB |
| 65 | 274,625 | ~7–8 MB |
A 65 grid has about 7.6 times as many points as a 33 grid, so the spacing between points is roughly halved. The difference is simply how much of the color space is interpolated rather than stored.
2. When it barely matters
- Manufacturer log conversion LUTs (S-Log3 to Rec.709 and similar): the curves are smooth, so interpolation error is tiny.
- Typical grading looks: gentle contrast, saturation and hue moves are hard to tell apart at 33.
- 8-bit delivery: if the final file is 8-bit H.264, its quantization error is larger than the LUT interpolation error.
3. When 65 is worth it
- Display calibration LUTs: correcting a panel means bending specific regions precisely, which is why calibration software commonly recommends 33 or larger, ideally 65.
- Looks with sharp transitions: selective color changes or film emulations that shift hues strongly over a narrow range can show banding or hue jumps at the edges with a 33 grid.
- Baked multi-step LUTs: color space conversion plus look plus output transform in one LUT has more curvature, so grid resolution matters more.
4. Compatibility and performance
Desktop editors generally read both 33 and 65, but external monitors, recorders and in-camera LUT slots may support limited sizes. Check the manual for supported grids (some only take 17 or 33). An unsupported size may fail to load or be downsampled. Stacking several 65 LUTs in real-time playback is slightly heavier, though rarely noticeable on a modern GPU.
5. Test it yourself
- Export the same look at both sizes (DaVinci Resolve: right-click the node → Generate LUT → 33 Point Cube / 65 Point Cube).
- Use a gradient ramp and real footage with skin tones and sky as test sources.
- Stack the same clip on two tracks and apply the 33 LUT to one and the 65 LUT to the other.
- Set the top track’s blend mode to Difference. Only differing areas light up; a near-black frame means no visible difference.
- If something shows up, inspect that area on the waveform and vectorscope.
Summary
| Use | Grid |
|---|---|
| Log to Rec.709, on-set monitoring | 33 (17 if the device only supports 17) |
| Sharing grading looks | 33 |
| Display calibration | 65 where supported |
| Selective color, film emulation and other aggressive looks | Build at 65 and compare with Difference |