What a seamless pattern checker does
A seamless pattern checker tiles a single image the way a printer or a wall does, so you can see whether the repeat is invisible or leaves a hard line. This one adds a real edge-match test: it reads the pixels along each edge and scores how closely they line up.
That matters because a seam you miss on screen becomes a stripe running down a finished wall or a bolt of fabric. Checking the tile first is the difference between a clean repeat and a reprint.
How the check works
- Edge reading. The tool samples the column of pixels on the left edge and compares it to the right edge, then does the same for the top and bottom.
- Break measurement. A visible seam is a continuous line, so the verdict follows the longest unbroken mismatch along each edge. Busy artwork always has tiny scattered differences — those print seamlessly and are ignored.
- See it. Turn on Tile grid to watch how the tiles step in each repeat mode, and Show seams to mark in red exactly where an edge breaks.
A tile that passes this test tiles cleanly in every layout — full drop, half drop, and brick — because it’s the underlying edges that carry the repeat.
How to fix a seam that won’t line up
If an edge scores low, you have three common fixes. Nudge the offending motif so nothing is cut off at the border. Use the offset-and-heal method in your editor: shift the tile by half, then paint out the cross that appears in the middle. Or, when the artwork allows it, switch to Mirror mode — flipping alternate tiles makes any image meet itself at every edge, which is why it always scores clean here.
Full drop, half drop, brick — which repeat?
Full drop stacks the tile in a straight grid. Half drop shifts every other column down by half, the classic wallpaper repeat that hides the grid and flatters florals. Brick (or half-brick) offsets alternate rows sideways, like a running-bond tile. All three need the same seamless base tile; they only change how it steps across the wall. Preview each above to see which suits your motif.