---
id: KB-DI-007
url: https://app.codecontract.io/help/documents-and-ai/scanning-a-document-properly
idioma: en
categoria: documentos-ia
subcategoria: subir
audiencia: usuario
nivel: intermedio
actualizado: 2026-08-13
tambienEn: [es]
relacionados: [KB-DI-003, KB-PR-005]
citadoPor: [KB-DI-008, KB-DI-012, KB-DI-015]
---

# Scanning a document properly

_Five minutes of method that avoid half the reading problems._

**Responde a:** how to scan a document so it reads well · what dpi to scan at · photograph a document with a phone · the scan is too large

The quality of the original decides almost everything that follows: whether it reads well, whether you can search inside it, whether it has to be reviewed by hand. And fixing it costs five minutes at scanning time, against hours of review afterwards.

## The numbers that work

| Setting | Value | Why |
| --- | --- | --- |
| Resolution | 300 dpi | Enough to read; 600 weighs four times as much and gains nothing |
| Colour | Greyscale | Unless colour means something, such as a stamp |
| Format | PDF | Better than loose images: it keeps the page order |

## If you use a phone

**En corto**

- Lay the paper on a table, do not hold it.
- Light in front of you, not behind: your own shadow is the commonest cause of a bad result.
- Frame the whole page, straight, with no fingers or table edges.

A current phone in decent light matches a scanner. What ruins photos is not the camera, it is hurry.

> [!WARNING]
> If the paper is creased or the print is very faint, no scan will fix it. What is needed there is another original.

> [!NOTE]
> A document that already exists digitally should not be scanned: ask for the PDF. Scanning a printout of a PDF loses the text it already contained, which then has to be recognised by OCR.

**What about fifty pages?**

In one PDF, not fifty images.

**Is scanning in colour worth it?**

Only if colour adds something: a stamp, a blue signature, a chart.

**Can I crop the photo?**

Yes, to remove the table. Do not retouch anything else if the document may serve as evidence.

## Ejemplos

**A supplier's certificates read badly again and again.**

- The original is checked: hand-held photos with shadow
- This guidance is sent to them

→ From the next send onward reading comes back high-confidence and manual review stops.

**The scan comes out dark and cannot be read.**

- Redoes it with more light and no shadows

→ Reading works first time.

**It is scanned at very low resolution to keep it small.**

- Raises the resolution without exceeding the limit

→ The document goes in and also reads.

**The document comes out cropped at the edges.**

- Frames the whole document

→ No text is missing from the reading.

**Black text is scanned in colour.**

- Scans in whichever mode gives the best contrast

→ The file is smaller and reads better.

**Each person scans differently.**

- Agrees common settings

→ Quality stops depending on who scans.