How to use .cube LUTs live in your iPhone camera.

LUT stands for lookup table. A 1D LUT changes each channel on its own, like a tone curve. A 3D LUT takes red, green and blue together and gives back a new color, so it can do what curves cannot: turn greens teal without touching skin, or warm the shadows and cool the highlights at once.

The table cannot store every possible color, so it stores a grid. A 33-point LUT has 33 × 33 × 33 = 35,937 entries. Colors between grid points are blended from the eight nearest ones. Adobe’s Cube specification recommends tetrahedral interpolation for 3D tables.

Adobe published the Cube LUT Specification 1.0 in 2013, and almost every tool reads it. A file has a few keywords at the top, then one line per grid point with three numbers between 0 and 1. Red changes fastest, then green, then blue. This is the start of the Portra 400 look that ships with IIWII:

# comments start with a hash
TITLE "lutCreatorJs_25"
LUT_3D_SIZE 25

# first entry: black in, near black out
0.039216 0.043137 0.023529
0.050980 0.035294 0.023529
0.062745 0.043137 0.031373
… 15,625 lines in total

The specification also allows DOMAIN_MIN and DOMAIN_MAX for tables that cover a range other than 0 to 1, and LUT_1D_SIZE for 1D tables. DaVinci Resolve writes its own LUT_3D_INPUT_RANGE keyword.

Sources Adobe, Cube LUT Specification 1.0 (2013, archived copy); Apple, Core Image Filter Reference; FFmpeg ticket 10431 (2023). Checked in October 2026.

Video cameras record Log footage on purpose: a flat, grey image that keeps every highlight and shadow. A Log LUT turns that flat picture into a normal one by adding contrast and saturation. Apply the same LUT to a normal photo and it adds contrast and saturation a second time. Highlights clip, shadows block up and colors go loud.

Look at the name or the description before you import: Apple Log, F-Log2, S-Log3, V-Log or Log to Rec.709 mean video. For photos you want LUTs described as Rec.709, sRGB or for photos.

Fujifilm’s official film simulation LUTs are a good example. They are free and excellent, but they expect F-Log2 footage. IIWII’s built-in Fujifilm looks first convert the iPhone image into F-Log2 and only then apply the table. An imported LUT is applied directly, so a Fujifilm Log LUT will look too strong.

Sources Fujifilm, 3D LUT downloads; PetaPixel on Fujifilm’s F-Log2 film simulation LUTs (November 18, 2025). Checked in October 2026.

• Photoshop exports .cube files under File › Export › Color Lookup Tables, from global adjustment layers. Masks and blur do not carry over.
• DaVinci Resolve can generate a 17, 33 or 65 point .cube from any grade on the Color page.
• Camera makers such as Fujifilm and Panasonic publish free LUTs, mostly for their Log profiles.
• LUT packs you buy usually allow use in your own photos and videos, but not sharing or reselling. Check the license file.

Lightroom cannot export a .cube file, and Capture One does not read or write them natively.

Sources Julieanne Kost, Exporting Color Lookup Tables from Photoshop; Panasonic, Creator’s LUT. Checked in October 2026.

1. Save the .cube file to the Files app, from AirDrop, iCloud Drive or a download.
2. In IIWII, open Settings › Look Library and tap Import .cube LUT.
3. Tap Select .cube file. You can pick several at once.
4. Give it a name, or keep the file name, and tap Import.
5. Your LUT now sits in the look picker next to the built-in looks, live in the viewfinder.

From there it behaves like any other look. You can set its intensity from 0 to 120 percent, and on iOS 18 and later it works for video too, and the Look Manager can stack light, white balance and color adjustments on top. On iOS 15 to 17, IIWII’s Legacy mode imports and applies LUTs as well.

What to know before you import

• Stick to 17, 33 or 65 points per side.
• Use LUTs with the standard 0 to 1 range; custom domain ranges are not read.
• 3D LUTs only. Pure 1D tables do not import.
• The file stays on your iPhone. Nothing is uploaded or synced.

Sources IIWII 5.2 LUT import and rendering code, checked October 19, 2026.