Troubleshooting

Two kinds of problem. The first kind stops the job before it exports, with a message; there are nine of these and they are listed in full below. The second kind exports perfectly and goes wrong on the press, which is the expensive kind, so it gets the longer half of this page.

Every message that can stop a job

The first five are grid arithmetic and are usually a typo. The last four are dependencies between settings, and each of them is refusing a combination that would produce a physically wrong result rather than a merely odd one.

Problems that only appear on paper

The backs are upside down

The single most common production fault in imposed work, and it has two opposite causes with an identical symptom: either the 180° back-flip is off when the press turns the sheet about its short axis, or the flip is on and the printer driver is applying a rotation of its own. Two rotations of 180° cancel, so doing it twice looks exactly like not doing it at all.

Decide where the correction lives — in the imposition or in the driver, never both — then prove it with the one-sheet test on duplex and flip. Mark the leading edge of the blank sheet before it goes in, and turn the printed sheet the way the finished piece will actually be turned.

The backs are on the wrong positions

Different fault, different fix. If the content is the right way up but position 1 on the back carries what should be behind position 2, the sheet is being turned about the axis your imposition did not assume and the whole grid has mirrored. Check orientation and position separately when you inspect a test sheet; treating them as one problem is how people end up toggling settings at random.

The crop marks are there but the cutter cannot use them

Marks sit 3 mm outside the trim by default. If the bleed is 3 mm or more, the near end of every mark lands on the bleed — printed over artwork, and invisible in a dark corner. The cutter then works by eye and the job comes back crooked.

Either increase the mark distance to 4 or 5 mm, or reduce the bleed to 2 mm. The rule is that mark distance must exceed the bleed; they are one decision, not two. See crop marks.

The marks are clipped or missing at the sheet edge

Every outside trim edge needs 8 mm of clear sheet — 3 mm of distance plus a 5 mm mark. A block that fills the sheet leaves the marks nowhere to be drawn. Take 16 mm off each sheet dimension before solving the grid, and reduce the scale by a couple of per cent if the grid no longer fits. On A3 that means designing into 281 × 404 mm.

Pages overlap in the gutter

A strip of the neighbouring piece along one edge of every trimmed item. The cause is a bleed larger than half the gutter: with a 3 mm bleed and the default 1 mm Gap X, each page's bleed runs 3 mm into a 1 mm space and lands on its neighbour.

The arithmetic in full is on bleed and gutters.

The folded booklet reads out of order

Check three things in order. Is the mode actually Booklet, rather than 2-up N-Up? N-Up puts pages 1 and 2 side by side, which is not a book. Is the signature size the section you are really folding? And is the page count a multiple of four — a folded leaf is always four pages, and a 14-page document needs padding to 16 in the source before importing. See Booklet imposition.

The inner pages of a thick section trim short at the fore-edge

This is creep, also called shingling: the inner leaves of a folded section sit progressively further out because the fold has to travel around the thickness of the paper, so the trim takes more off them. Set the Booklet creep controls for your stock. Adjust the creep amount and choose the inward or outward direction. Inspect the preview, then print, fold and trim a proof to confirm the allowance. The paper-weight field does not calculate the creep setting automatically.

The cut piles are out of sequence

Cut & Stack guarantees the finished order only if the printed sheets reach the guillotine in press order and the cut piles are stacked in position order. A reversed delivery inverts everything downstream. Turn sheet numbering on, fan the pile before the knife, and confirm the top sheet is the number you expect. See slug line and sheet numbering.

If the problem is colour

It is not the imposition. FastImpose performs no colour conversion, applies no ICC profile and validates nothing against PDF/X — pages are carried through as vector form XObjects and their colour is exactly what it was in the source. A colour difference between the source and the printed sheet came from somewhere else in the workflow, most often the RIP. Format notes explains why that boundary is where it is.