A LUT is a small file that decides what a whole shoot looks like on the monitor, in the edit and in the first pass of the grade. When the team uses the wrong one, nobody notices until the colorist opens the project.
Most LUT trouble starts with how the files are handled. A typical case is a file called “look_final.cube” on three laptops, each copy slightly different.
In short
- A technical LUT converts a camera’s log to a viewing standard, and it only fits the exact log curve and gamut it was made for.
- A creative LUT carries a look, and you have to know whether it expects log or Rec. 709 before stacking it.
- Keep one LUT library per project, name every file with camera, conversion and version, and never save over an old version.
- Monitor through the LUT on set, record clean log, and use the same file in dailies, the edit and as the colorist’s starting point.
Technical LUTs and creative LUTs
A LUT (look-up table) maps every input color to an output color. A 1D LUT works on each channel separately, like a curve, and a 3D LUT can move any color anywhere, which is what conversions and looks need.
A technical LUT is a conversion. It takes a log curve such as ARRI LogC4, Sony S-Log3 or Canon Log 3 to a viewing standard, usually Rec. 709. Camera makers publish these, and each one is built for a single log curve and gamut.
A creative LUT carries a look, such as a film emulation, a brand’s color or the style the DP and colorist built in testing.
Some creative LUTs expect log input and do the conversion inside. Others expect Rec. 709 and go after a technical LUT.
The LUT mistakes that cost a day
Most color disasters on a shoot come from five mistakes, and every one of them is cheap to prevent:
- The wrong technical LUT. A LogC3 LUT on LogC4 footage, or an S-Gamut3 LUT on S-Gamut3.Cine, looks almost right, which is why nobody catches it on set.
- A double conversion. A creative LUT built for log input placed after a log-to-709 LUT converts the footage twice, and the result looks crushed and oversaturated.
- The look baked into the recording. Some cameras can record with the LUT applied. On log footage that throws away the latitude you shot log for.
- A review export straight from log. The client gets a grey, flat picture and writes color notes on a grade that doesn’t exist yet.
- A tweaked LUT saved under the old name. Two people now have two looks with the same file name, and the shots no longer match.
How to organize and version LUTs
Keep one LUT library per project, on the shared storage, with technical and creative LUTs in separate folders. Camera makers’ LUTs stay exactly as downloaded, with a note of where and when they came from.
Put the camera, the conversion and the version in every file name, so the right LUT can be found without opening it:
ARRI_LogC4-AWG4_to_709_v1.cube
SONY_SLog3-SG3C_to_709_v1.cube
ACME_launch_look_v03.cube
ACME_launch_look_v04.cube
A changed LUT gets a new version number, never the old name. Add a short text file to the folder with what changed, who changed it and when. The same habit that keeps video files from ending up as final_FINAL works here.
Only the colorist or the DP writes to the creative folder. Everyone else reads. On most shared drives that’s a folder permission, and it stops the “I just brightened it a bit” version from spreading.
Freeze the show LUT before the first shoot day. Once dailies start, a new look means agreeing on it with the DP and the colorist and sending the new version to everyone at once.
Carrying one look from the set to the grade
The goal is that the director, the editor, the client and the colorist all start from the same picture. That takes the same file at every step:
- Before the shoot. The DP and the colorist build or pick the look on camera tests and export it as .cube, usually 33 points. It goes into the project’s LUT library and onto the camera or monitor cards.
- On set. The LUT goes on the monitor outputs and the camera records clean log. Per-scene tweaks are noted as CDL values (slope, offset, power and saturation), which post can apply exactly, instead of new LUTs.
- Dailies. The same LUT, plus any CDL, goes on the dailies transcodes, so the director watches the night’s footage with the look approved on set. The dailies review post covers that night.
- The edit. The editor applies the LUT without touching the media: in Premiere through the Lumetri Color panel, in Resolve on a node, from the LUT folder set in Project Settings > Color Management. If the proxies were made with the LUT baked in, the originals will look flat on relink, so add it to the timeline first.
- The grade. The colorist removes the editor’s LUT and starts from log, with the technical transform or the project’s color management, using the show LUT as a reference rather than the answer.
- Review and delivery. Every export the client sees has the look baked in. How to run that round is in our post on reviewing color with a client.
How this works in RecReview
RecReview doesn’t apply LUTs and doesn’t hold a LUT library. The player shows the file you exported, so the review copy needs the look baked in. A log export arrives at the client looking grey.
Anyone watching can switch the player to Original, which plays the file you uploaded instead of the lighter streaming copy. For a color round, that takes compression out of the argument.
Every regrade you upload becomes a numbered version on the same task. Compare plays two versions in sync, side by side, split or overlaid, so the client checks the new grade against the last one instead of against memory. More in comparing two versions.
The client comments on the frame and can draw on the picture to circle the shot that looks off, and the colorist answers in the same thread.
The task can carry the LUT pack as a .zip attachment, along with reference stills in JPEG or PNG, up to 50 MB per file. Everyone in your workspace can open the task’s attachments, and the client never sees them, so a freelance editor gets the same file as the colorist.
