Poster Printing Tips: Get a Clean Multi-Sheet Poster at Home

Tiled printing only works if every sheet comes out at exactly its designed size. Each page of a RasterPoster PDF equals the paper size, so printing at 100% gives a true 1:1 result. Any scaling, even 97%, shrinks every sheet slightly, and the errors add up across the grid until the edges no longer meet.

On Windows look for “Actual size” or a scale field set to 100%; on macOS Scale should read 100% with “Scale to fit” off. PDF viewers add their own layer, so check the viewer’s dialog as well as the printer driver.

• Choose “Actual size” or Scale 100%. Never “Fit to page”, “Shrink oversized pages” or “Scale to fit”.
• Turn off borderless printing. It enlarges the page slightly to bleed off the edges, which breaks the 1:1 size.
• Match the paper size in the dialog to the paper in the tray — A4, US Letter or A3 — and keep portrait or landscape as designed.
• Use the same quality setting for every page. Mixing “Standard” and “High” in one poster produces visibly different tiles.
• Print one test sheet first and measure the image with a ruler before sending the whole job.

Ordinary 80 g/m² copy paper is fine for a draft, but it wrinkles under heavy ink and shows tape through from behind. For a poster you plan to keep, 100–120 g/m² paper is flatter, more opaque and still easy to feed. Heavier photo papers look great but are awkward to trim and join.

Matte paper is the forgiving choice: it hides seams, does not reflect light at the joins and takes glue and tape well. Glossy paper gives richer colour, but every slight misalignment catches the light.

• Use paper from the same pack for the whole poster. Different batches can differ in brightness and tint.
• Load enough sheets for the full job before you start so nothing gets swapped halfway.
• Set the paper type in the dialog to match what is in the tray; it changes how much ink the printer lays down.

Colour drift between tiles can only be cured by reprinting. Prevention is easy: print all the pages in one session, from one file, with one set of settings.

• Check ink or toner levels before you start. A cartridge running low mid-job is the classic cause of one faded or tinted tile.
• Do not change colour management, “Draft” or “Eco” options partway through.
• Let inkjet prints dry for at least 15–30 minutes before stacking, trimming or taping. Damp ink smudges and paper can cockle.
• Prefer the PDF. The ZIP of JPG pages suits sharing or a print shop, but photo apps tend to rescale JPGs.

Most home printers cannot print to the very edge of the sheet; the non-printable zone is often 3–5 mm. That is why every RasterPoster page has a 10 mm white margin, with crop marks showing exactly where the image ends. Each sheet also carries a label such as R2C3 with “Page 5 of 9 · row 2, column 3”, a mini map of the grid and a reminder to print at 100%.

Lay the sheets out in grid order before cutting, so you never trim the wrong edge of the wrong page.

• Use a sharp craft knife with a metal ruler on a cutting mat, or a guillotine or rotary paper trimmer. Scissors wander and leave wavy edges.
• Line the ruler up with both marks on an edge, not just one, so the cut stays square.
• Replace or snap the blade when it starts to drag; a dull blade tears the paper fibres and leaves a fuzzy seam.
• For edge-to-edge seams, trim every edge that meets a neighbour. With overlap edges enabled, trim only the top and left (see below).

A butt joint means trimming all inner edges exactly on the marks and pushing the sheets flush together. Done well, it gives the flattest result, but every millimetre of cutting error shows as a gap or a hard line.

The “Overlap edges” option is safer for most people. It adds a 5 mm strip of extra image on the right and bottom of each sheet, marked with a dashed line. Trim only the top and left, then lay each sheet onto its neighbour so the cut edge sits on the dashed line. Because the image continues underneath, small cutting errors disappear.

• Pick overlap for your first poster, on glossy paper, or whenever you trim with scissors.
• Pick flush seams when you want a perfectly flat surface for framing and trust your cutting.

Work on a large clean table or the floor. Start with R1C1 in the top-left corner and build outward row by row, checking each joint before fixing it; the labels and mini maps reveal a misplaced sheet before it is stuck down.

• Tape from behind with matte or paper tape so nothing shows on the front; run short strips across each joint, then one long strip along it.
• For overlap joints, a thin line of glue stick along the overlap strip holds well and stays flat.
• Spray adhesive gives the most even bond on foam board; use it in a ventilated space.
• Foam board or thin card makes a rigid panel that will not curl.
• To hang straight on a wall, use removable adhesive strips or poster putty at the corners and along the joints, and check level with a spirit level.

The symptom usually points straight at the cause. Check this list before reprinting everything.

• Pages don’t line up or the image drifts across the grid → the print was scaled. Reprint at 100% / “Actual size” with borderless off.
• Thin white stripes between sheets → the margin was not fully trimmed, or flush seams were cut slightly inside the lines. Try overlap edges.
• Horizontal bands or streaks → print quality too low or clogged nozzles. Run the printer’s nozzle check and head clean, then print at a higher quality setting.
• Colour shift between pages → mixed settings, different paper or a low cartridge. Reprint the odd sheets with identical settings.
• Wavy or rippled sheets → too much ink on thin paper or taping before the ink dried. Use heavier paper and let prints rest.
• Image looks soft up close → the source photo is too small for the poster size. Choose fewer pages or a higher-resolution image; 150–300 DPI output only helps if the source has the detail.