Oversized work
Seam bleed and why gaps happen
A butt join has to close without a white line. Bleed is what makes trimming forgiving, and the seam itself falls out of the crop rather than being drawn.
5 min read
Panelling runs from the command line, not from the web app. Nothing on a screen produces the seams described here.
What seam bleed is
Bleed is artwork printed past the seam cut, which you trim off. It defaults to 1 cm, which covers most trimming.
Without it, two panels butted together leave a white line wherever the blade tolerance falls short. With it, the trim can wander by a few millimetres and there is still artwork behind the join.
The cost is page area: the artwork a panel can carry is its page width less two bleeds. At 1 cm on a 102 cm press that is 100 cm of finished artwork per panel, and the plan the tool prints accounts for it.
Bleed is not overlap
| Bleed | Overlap | |
|---|---|---|
| What it is | Artwork printed past the seam and trimmed away | Finished artwork deliberately shared by both neighbours |
| The join | Butt — the two panels meet edge to edge | Lapped — one panel sits over the other |
| Default | 1.0 cm | 0 |
Overlap is a different join, not more bleed. Set it when the material or the substrate wants a lap; leave it at 0 for a butt join and let the bleed do the work.
The seam is not a line somebody drew
The artwork is cropped at the seam before its outline is found, so the edge of the crop IS the seam. Two neighbouring panels cut the same line from opposite sides, and the join closes because it is one line found twice, not two lines that were meant to agree.
Drawing a straight line and hoping it met the silhouette would leave a step at every join — at exactly the place two pieces of material are supposed to become one.
Why a gap or a step appears anyway
Three things go wrong at a join, and each one has a look you can recognise on the bench. None of them is something a setting causes, and none is something a setting fixes — so the useful skill is spotting which of the three you are holding.
The seam is curved rather than straight
A seam edge should be dead straight from one end of the panel to the other. If it bows, the panel is wrong rather than mis-trimmed, and its neighbour will not close against it however carefully you cut.
Run the job again. If the seam comes back curved a second time, send us the artwork and the finished size you asked for.
A diagonal line runs straight across a panel
A cut running corner to corner across the middle of a panel is not part of the artwork and is not a scallop or a fold. Nothing you can set produces it, so do not go looking through the settings for the cause — send us the panel and the artwork it came from.
The cut sits on the page edge
Every panel page is the artwork plus the clearance, so there is always a margin between the cut and the edge of the sheet. A 60 cm cut on a 60 cm page has none, and there is nothing left to hold the piece while it is trimmed. That is worth catching before three sheets are printed rather than after.
One more, about the print rather than the cut
If a panel's printed edge looks stepped and hard, that is the print and not the cut. The cut edge is a hard yes or no because the blade is; the printed edge should keep the soft fade the artwork had. A stepped printed edge on a panel is worth sending to us — the cut path beside it is unaffected either way.