Actual Size Lab guide

A4 size in pixels, millimetres and inches.

Use this table when preparing an A4 bitmap, but remember that physical page size and source sampling are separate decisions.

A4 physical dimensions

A4 paper measures 210 × 297 mm, which is approximately 8.27 × 11.69 inches. The A-series relationship is defined by ISO 216. Rotating the page changes orientation, not dimensions.

A4 pixels at common sampling values

SamplingPortrait pixelsApprox. megapixels
72 PPI595 × 8420.50 MP
96 PPI794 × 11230.89 MP
150 PPI1240 × 17542.18 MP
300 PPI2480 × 35088.70 MP
600 PPI4961 × 701634.81 MP

Values are rounded to the nearest whole pixel. Different software may round one dimension differently by one pixel.

How to calculate A4 pixel dimensions

width pixels = 210 ÷ 25.4 × PPI
height pixels = 297 ÷ 25.4 × PPI

At 300 PPI, the width is 2480.315 pixels and the height is 3507.874 pixels, which round to 2480 × 3508.

Which value should you choose?

Use the resolution appropriate for the job. A screen preview does not need a 600 PPI A4 bitmap. A close-viewed photo or detailed print commonly targets around 300 PPI. Line art and specialised reproduction may benefit from different workflows. Larger files also consume more memory and storage.

Why the printer creates PDF instead of a full-page bitmap

Actual Size Lab resamples only the placed image and embeds it onto a physical A4 PDF page. This avoids creating an unnecessarily huge full-page 600 PPI canvas when the requested image is small. It also preserves explicit page dimensions for the print dialog.

Reference

ISO 216:2007 — writing paper and trimmed sizes.

About this guide

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