Rayo PDF GOGlossary
Resolution and DPI: what it is and what it is for
What dots per inch means and how much resolution a scan needs.
DPI (dots per inch) measures how many pixels fit in each inch of a printed or scanned image. The higher the DPI, the more detail and the larger the file.
To read a document on screen, about 150 DPI is enough. For good-quality printing, 300 DPI is recommended. Going much higher (600 DPI or more) is only needed for blueprints, archival photos or for OCR to read very small print.
A very high-resolution scan is the most common cause of a PDF that is "impossible" to send by email: it is very large without any visible difference to the eye.
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Frequently asked questions
What resolution should I choose for scanning?
For text documents, 200 to 300 DPI is usually enough.
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