What Is DPI, and Why It Matters Less Than You Think
Scanning at the highest DPI setting feels safe, but it's usually the reason your file is too big. Here's what DPI actually controls.
If you've ever scanned a document and seen options like 150, 300, or 600 DPI, and picked the biggest number "to be safe," you're not alone — and you probably made your file unnecessarily large for no real benefit.
What DPI actually is
DPI stands for dots per inch — literally how many pixels are packed into each inch of the scanned image. Higher DPI means more pixels means more detail captured, but also a much bigger file.
The catch: past a certain point, more DPI doesn't make the document more readable — it just makes the file bigger. A printed page scanned at 300 DPI already captures every letter with total clarity on a screen. Scanning the same page at 600 DPI roughly doubles the file size while adding detail nobody can perceive when viewing it digitally.
When DPI actually matters
- You're printing the scan at full size later — higher DPI keeps text and images crisp when printed, since print resolution needs are higher than screen resolution needs.
- The document has very fine print or fine detail (small legal text, intricate stamps) that needs to survive zooming in significantly.
When it doesn't matter (most concours/portal uploads)
- The document is being viewed on a screen by a reviewer, not printed.
- The portal has a strict file size limit — which almost all concours portals do.
- The document is standard printed text, not fine print or detailed artwork.
In this — by far the most common — case, 150–200 DPI is plenty, and will produce a file that's a fraction of the size of a 600 DPI scan with no visible loss of legibility on screen.
What actually matters more: file size, not DPI
Portals don't reject files for "wrong DPI" — they reject files for being too many kilobytes. If your scanner or scanning app only lets you pick DPI and not target file size directly, the fix is simple: scan at a moderate DPI (150–200), then run the result through a size-target compressor that hits the portal's exact limit. That gives you control over the number that actually decides whether your dossier gets accepted.