Image resolution: what you need for print

Pixels and print size

A print is only as sharp as the pixels that make it up. The printer spreads those pixels across the paper, and the density of that spread is measured in pixels per inch (PPI). Higher density means finer detail and smoother gradients; lower density means the individual pixels become visible as blocky squares.

For standard print quality you want about 300 PPI. A 3000 × 2000 pixel photo prints cleanly at roughly 10 × 7 inches. The same photo stretched to 20 × 13 inches is only 150 PPI, which is acceptable for a poster viewed from a distance but soft in a hand-held print.

How to calculate the pixels you need

Multiply the intended print size in inches by the target PPI. A 6 × 4 inch photo at 300 PPI needs 1800 × 1200 pixels. An A4 page (about 8.3 × 11.7 inches) needs roughly 2480 × 3508 pixels.

Run the calculation in reverse to check an existing file: divide the pixel width by the intended width in inches. A 1200-pixel-wide image printed 8 inches wide gives only 150 PPI, which will look soft for a photograph.

Common print sizes at 300 PPI

A 4 × 6 inch print needs about 1200 × 1800 pixels. A 5 × 7 inch print needs 1500 × 2100 pixels. An 8 × 10 inch print needs 2400 × 3000 pixels. A 12 × 18 inch poster needs 3600 × 5400 pixels at full 300 PPI, though 150 PPI is usually fine for a large poster seen from a few feet away.

Treat these as targets, not hard limits. 300 PPI is a high standard; 200 PPI is generally acceptable for photographs, and lower values can work for large formats viewed at a distance.

Converting formats cannot add detail

This is the most common misunderstanding about print preparation. Changing a file from PNG to JPG, or from WEBP to TIFF, does not create new pixels. It only changes how the existing pixels are stored.

If you are exporting a screenshot or a small web image for print, check the pixel dimensions first. A tiny image cannot become sharp by converting formats, no matter how good the converter is. Upscaling can smooth the edges, but it cannot recover detail that was never captured.

If an image is genuinely too small, the only real options are to use a larger source file, rescan the original at a higher resolution, or accept a smaller print size.

Format choices for print

JPG is the standard for photographic prints because it keeps file sizes reasonable while preserving smooth tones. Use the highest quality setting available, because print amplifies compression artifacts that are invisible on screen.

PNG is a good choice for graphics and text-heavy artwork that must stay crisp, such as charts, diagrams, and posters with flat color. Avoid repeatedly editing and re-saving a JPG before printing, since each save adds a little more loss.

TIFF remains a common choice for professional printing and archiving because it stores data without lossy compression. The files are large, but they preserve the image exactly for further editing.

Color: an important print caveat

Screens emit light in RGB, while most printers mix ink in CMYK. Some vivid and neon colors that look brilliant on a display cannot be reproduced in ink, and prints often appear slightly darker and less saturated than the screen preview.

This is normal and expected. If color accuracy is critical, check with your print service about their preferred color profile, and be prepared to adjust brightness and saturation before exporting.

A practical pre-print checklist

Confirm the pixel dimensions give you at least 200 to 300 PPI at the final print size. Crop and resize first, then convert the format. Export at the highest quality setting, and keep the original untouched as a master copy.

Whatever the destination, export at the highest quality the source allows and keep a copy of the original image so the print can be repeated or corrected later.