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Creating and Using Color LUTs

Saving a look so you can apply it in one click, forever

In This Lesson

What a LUT Is

A LUT (Look-Up Table) is a saved recipe that maps every possible input color to an output color. Instead of re-doing a ten-step grade on each photo, you bake that grade into a LUT once and apply it instantly to any image. LUTs are how film and video keep hundreds of shots looking identical — and they work just as well for a photo series.

🎨 An Analogy

A LUT is a color translation dictionary. Hand any color to the dictionary and it returns the graded version. Because the dictionary never changes, every image gets the same treatment.

How LUTs Work

A full-color LUT is a 3D table: for each combination of Red, Green, and Blue input, it stores a graded RGB output. Applying it means looking up each pixel's color and swapping in the stored result. Because it is just a lookup, applying a LUT is fast and perfectly consistent — the same input always yields the same output.

FormatWhere it comes fromGIMP support
.cubeVideo apps, LUT packsNot native; convertible / via plugins
HaldCLUT (PNG)An image you grade yourselfApplied via the G'MIC plugin
GIMP Curves presetSaved from the Curves dialogNative — reusable per-tool settings

LUTs in GIMP: The Reality

Out of the box GIMP does not load .cube LUT files, but it has two practical routes to the same result:

  • Save tool presets. The Curves, Levels, Color Balance, and Hue-Saturation dialogs let you save named settings you can reload on any image — a lightweight, single-tool "LUT."
  • HaldCLUT via G'MIC. The free G'MIC plugin can apply a HaldCLUT — a special image that encodes a full 3D color map. This gives true, portable LUT behavior.

💡 Easiest Reusable Look

For most photographers, the simplest reusable grade is a saved Curves preset plus a saved Color Balance. Reload both on the next photo and you have re-applied your look in two clicks — no plugins required.

Creating a HaldCLUT

A HaldCLUT is astonishingly clever: you grade a special "identity" image, and that graded image becomes the LUT.

  1. Obtain a neutral identity HaldCLUT image (G'MIC can generate one, or download a standard 8×8×8 / 512×512 identity PNG).
  2. Open it in GIMP and apply your full grade to it — the exact Curves, Color Balance, and Hue-Saturation moves of your look.
  3. Flatten and export it as a PNG. This file now encodes your entire grade as a color map.
flowchart LR A[Identity HaldCLUT] --> B[Apply your grade] B --> C[Export graded PNG] C --> D[Reusable LUT for any photo]

Grade the identity image once; the result is a portable LUT.

Applying a LUT

With G'MIC installed (Filters → G'MIC-Qt), open your target photo and choose the color mapping filter that applies an external HaldCLUT (under G'MIC's Colors category). Point it at your saved HaldCLUT PNG and the whole graded look transfers in one step. Adjust the filter's opacity/strength to blend the look with the original.

🎓 Build a Look Library

Save several HaldCLUTs — "warm summer," "cold thriller," "matte film" — in one folder. You now have a one-click grading library you can share, back up, and reuse across projects. Consistency becomes effortless.

When to Use LUTs

  • Series consistency — apply the identical grade to every photo in a set.
  • Speed — skip re-building a complex grade for each image.
  • Sharing a look — hand a collaborator your HaldCLUT and they get your exact style.

⚠️ LUTs Are Not Magic

A LUT assumes every image starts from the same corrected baseline. Apply one to an uncorrected, casted photo and it bakes the cast into the look. Correct each image first, then apply the LUT for the creative grade.

Practice Activities

  1. Preset pair. Grade a photo, then save the Curves and Color Balance settings as presets. Reload them on two more photos.
  2. Make a HaldCLUT. If you have G'MIC, grade an identity HaldCLUT and export it, then apply it to a fresh image.
  3. Consistency test. Apply your look to five different photos and check that they now feel like one set.

Summary

✅ Key Takeaways

  • A LUT saves a full grade as a reusable color map for instant, consistent application.
  • GIMP has no native .cube support, but offers saved tool presets and HaldCLUT via G'MIC.
  • Create a HaldCLUT by grading an identity image — the result is the LUT.
  • Apply HaldCLUTs through G'MIC's color-mapping filter; build a library of named looks.
  • Always correct first — a LUT amplifies whatever baseline it receives.

➡️ What's Next

Next, a classic grading technique in detail: Split Toning.

Additional Resources