Repair a banded sky with Pixelmator Pro

Imagine a JPEG of a lighthouse at dusk: its sky has visible colour steps, yet the railings are sharp. The aim is to smooth the gradient while keeping those little edges.

Pixelmator Pro includes Deband among its machine-learning tools. This walkthrough follows Apple’s Mac documentation; we have not executed the edit.[3]

Use Pixelmator Pro on macOS 26. Apple offers the Mac app as a standalone purchase or through Creator Studio.[2]

Prepare the repair

Open a copy of your JPEG. Choose Image → Color Depth → 16 Bits/Channel, then OK. Apple recommends 16-bit depth before Deband.[1]

Colour depth determines how many values pixels can store. Changing that setting prepares the document; Deband performs the repair.[1]

Select the image layer in Layers, choose Format → Deband, and drag the split-view divider: original left, repaired right.[1]

In the lighthouse exercise, compare three places: a broad stretch of sky; the sky beside the building; and the railings. Look for smoother transitions in the first two, while checking that the thin lines remain distinct. This gives the comparison a specific purpose beyond making the whole picture look softer.

Click Done to apply the result.[1]

Keep the output

Choose File → Export, name and locate the copy, then choose TIFF from Format and click Export. TIFF is lossless and supports 16-bit colour.[1]

Reopen the TIFF and check Image → Color Depth shows 16 Bits/Channel.[1]

Compare the same patches of sky and railing again, both close up and at the intended viewing size. Keep the original alongside the exported copy. A useful repair should leave the lighthouse’s fine structure worth looking at.

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