Find the cause of a white line.

Start with the exported tile

Keep your layered original and export a fresh copy of the tile. Open that file in another viewer and repeat several copies. If the same line follows every join, inspect the outer pixel rows and columns. A strip of white or transparent pixels, a shifted edge copy or a crop that is slightly too large can all interrupt the pattern.

If the line appears at one zoom level but disappears at another, it may be a preview artefact. The viewer is fitting image pixels into screen pixels and can show a hairline where scaled images meet. Do not paint over a clean file merely to conceal one preview. Compare the exported pixels and another display before deciding.

Check position before adding paint

Edge copies need exact positions. A motif copied to the opposite side must move by the full tile width or height while keeping its other coordinate. Small freehand nudges can produce a visible step. In Procreate, work carefully with Transform and Snapping, retain a full-canvas reference when needed and avoid repeatedly scaling the same raster layer.

Also check your background. It should cover the complete canvas if the design needs an opaque background. A transparent PNG is useful for motifs, but an unintended transparent strip is not a substitute for the intended cream, pink or dark background.

Repair the cause in the source

Enlarging the tile or changing its DPI label will not remove a structural gap. Adding a blurred border may conceal one area while creating a new visible band. Keep each repair tied to the fault you found.

Inspect once more at useful scales

Use Repeat Inspector to examine the exported joins and magnify suspicious areas. Check the centre, all edges and the corners, then look at a wider repeat. Repeat the check after a crop, texture or other edit that changes pixels near the boundary.

Download the clean practice PNGDownload the PNG with a one-pixel gap

When the new export looks continuous in repeated views, keep that checked source alongside your project file. Use a separate mockup image to present it; a photograph of a product cannot prove that the underlying tile joins.