Test 10 cm before printing your photos.
Print this page on A4 at 100% or Actual size and disable browser headers and footers. Measure the distance from 0 to 10 with a real ruler. This is a manual scale check, not automatic printer calibration.
Print scale test — the distance from 0 to 10 should be exactly 10 cm.
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A4 · 100% / Actual size · Check with a physical ruler. Printer settings may affect the dimensions.