Print every tile at 100% using the selected paper. Lay the sheets out in the numbered row order before trimming. Cut one side of each shared overlap, align the repeated image detail and tape from the back. Keep an outer overlap until you have checked the full poster.
Before you print
Use Actual size or 100% in the PDF print dialog. Match the paper format and disable any further resizing in the printer driver. The preview shows the PDF layout, not a guarantee of your printer’s printable area. Start with ordinary paper and measure before using photo paper.
The 20 mm scale check
The optional control square is 20 × 20 mm. It reserves space at the bottom of every sheet, so enabling it may add a page. Compare both measured sides with 20 mm. For example, a 19 mm side indicates 95% scaling. Do not enlarge the photo to conceal a scaling problem.
Job limits
Jobs are limited to 40 photos, 30 MB and 50 megapixels per image, 50 copies per photo and 80 PDF pages. Poster dimensions can reach 2000 mm per side, but page count and device memory may limit a job earlier. The automatic arrangement is practical rather than guaranteed to use the fewest possible sheets.