LUT vs. filter: what actually differs

The comparison in one table

	LUT	Filter
What it is	A table mapping input RGB to output RGB, per pixel	Any effect an app chooses to bundle under a name
Portability	The same .cube file works in LUTLINE, DaVinci Resolve, Final Cut Pro, Premiere Pro	Locked to the app that made it
Input expectation	Explicit: technical LUTs expect a specific Log profile, creative LUTs expect Rec.709	Usually undefined; applied to whatever the app is showing
Spatial effects	None — a LUT cannot blur, sharpen, add grain or vignette	Often included, mixed with the colour change
Intensity	A blend between original and transformed pixel, 0 % is exact identity	Varies; sometimes scales every sub-effect at once
Predictability	Deterministic; the same input always gives the same output	May depend on resolution, app version or device
Authoring	Exported from grading software or built from measured film	Designed inside the app, rarely exportable

Why the distinction matters on iPhone

Most phone "filter" apps were built for photos: they take a display-ready image and apply a styled effect. Video from a modern iPhone, drone or mirrorless camera is often not display-ready — it is Log, and it needs a technical conversion before any style makes sense. A filter app has no concept of that step; it styles the flat image and the result looks muddy. A LUT app that respects the order — convert, correct, then look — starts from a correct picture.

The second reason is consistency across tools. If you grade a clip on the phone with a .cube and later cut the project on a desktop, the same file gives the same look there. A filter cannot follow you.

What LUTs are bad at

Being honest about the limits is part of using them well.

• Texture. Grain, halation, bloom, dust and vignettes need neighbouring pixels. That is why LUTLINE has a separate Film stage after the colour is done, rather than pretending a LUT can do it.
• Exposure and white balance. A LUT is fixed. If the shot is a stop under, the LUT cannot know. Corrections belong before the look, in the Adjust stage.
• Out-of-range values. A .cube is defined on 0–1. Values outside are clipped at the table's edge, so a LUT applied to un-corrected highlights can flatten them.

So which should you use?

For video, use LUTs and treat filters as a convenience for social snapshots. Use the camera maker's technical LUT for the conversion, correct the image, then a creative LUT for the look, then texture. If an app only offers "filters" with no way to load a .cube and no explicit Log conversion, it is a photo tool wearing a video icon.

How LUTLINE draws the line

LUTLINE keeps the two ideas apart on purpose. The Source and Look stages are LUTs — the manufacturer's conversion table and a creative .cube, bundled or imported. The Adjust stage is arithmetic on the image (exposure, contrast, curves). The Film stage is the spatial texture a LUT cannot produce. The Recipe sheet shows all of it in order, and preview and export run the same graph. Nothing in the app is a "filter".

Frequently asked