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Image formats

PNG vs TIFF for scanned documents

By DeckleUpdated

For scanned documents, choose TIFF when you want a whole multi-page document in one lossless file, and PNG when you want each page as a separate, lossless image that opens in any app. Both keep every pixel. For a PDF, PNG pages through PNG to PDF stay lossless, while TIFF to PDF re-encodes each frame as a high-quality JPEG.

PNG to PDF

One file can hold several frames

Frame 1

Cover

Frame 2

Table

Frame 3

Signed page

3 included frames → 3 planned PDF pages

Example · count included decoded frames, not TIFF filenames.

PNG vs TIFF for scans at a glance

PNG TIFF
Compression Lossless Usually lossless (LZW, Deflate or none)
Several pages in one file No, one page per file Yes, multi-page TIFF
Opens in browsers and common apps Yes Not everywhere; some show only the first page
Scanner metadata such as DPI Limited Rich tag set
Typical use Single pages, screenshots, the web Scanning, archives, fax, print
In a Deckle PDF Pixels kept exactly Saved as quality-90 JPEG, one page per frame

Apple's Photos app describes both TIFF and PNG as lossless formats (Export photos on Mac). The real differences are packaging, compatibility and what happens when you make a PDF.

Choose TIFF when

  • A document has many pages and you want one file per document, not one per page.
  • You are building an archive and want a lossless master with scanner details stored in the file.
  • A system asks for it, such as document-management or fax software.

A multi-page TIFF keeps a 30-page contract in one file, in page order. What is a multi-page TIFF? explains how the frames are stored.

Choose PNG when

  • You scan single pages, such as a certificate, a drawing or a letter.
  • The image must open everywhere, including browsers and phones.
  • The PDF must stay lossless. PNG to PDF keeps every pixel; this matters for fine line work, engineering drawings and small print.
  • You will edit pages individually, for example cropping or cleaning up one page.

What happens when you make a PDF in Deckle

From PNG: PNG to PDF stores each page's pixels exactly with lossless compression. Each PNG becomes one page, in the order of the list. Animated, interlaced and 16-bit PNGs are refused.

From TIFF: TIFF to PDF decodes every frame and saves it as a JPEG at quality 90 on a white background. Colour and greyscale scans look the same at normal zoom. Sharp black-and-white text can show faint softening when zoomed far in, and a compact black-and-white TIFF can produce a larger PDF. TIFF tags are not carried over.

Your scan For a PDF, use
A multi-page TIFF of ordinary letters or forms TIFF to PDF, Fit inside A4
Fine drawings where every pixel matters Save pages as PNG, then PNG to PDF
A folder of single-page PNG scans PNG to PDF, ordered with the arrows

Either way, choose Fit inside A4 for paper documents. A 300 DPI scan otherwise becomes a page about 34 × 49 inches, because page size comes from pixels, not the DPI tag. See image DPI vs PDF page size.

How to convert PNG scans to a PDF

  1. Open PNG to PDF and choose Select files, or drop the page scans onto the page.
  2. Put the pages in order with the up and down arrows. Deckle follows the list, not the file names.
  3. Choose Fit inside A4 and Portrait.
  4. Choose Create PDF and check that the page count matches the paper.

Scanning settings that matter more than format

  • Resolution. 300 DPI is enough for reading and printing text. At 300 DPI an A4 page is about 8.7 megapixels, within the 16-megapixel limit on a computer, so every pixel is kept. At 600 DPI it is about 35 megapixels: a computer scales it down to 16 megapixels, so the extra resolution is lost, and iPhone and iPad refuse it.
  • Colour mode. Greyscale suits most text documents and makes smaller files than colour.
  • Compression. For TIFF, LZW or Deflate keep it lossless and readable by Deckle; fax (CCITT), PackBits and JPEG compression are refused.

Tips

  • Scan straight to PDF if you only need a PDF and no lossless master.
  • Keep one format per batch. Each Deckle tool takes one format, so a mix of PNG and TIFF needs two runs and a merge.
  • Check page counts. TIFF to PDF's result screen states how many pages were created, one per frame; compare it with the paper.
  • Avoid JPG for text scans. It softens edges; PNG and TIFF do not.

Frequently asked questions

Is TIFF better quality than PNG?

Not inherently. Both are lossless. TIFF's advantages are multi-page files and richer scanner metadata.

Which makes a better PDF in Deckle?

PNG, if every pixel matters, because PNG to PDF is lossless. TIFF to PDF saves frames as high-quality JPEG.

Can I convert a multi-page TIFF into PNG pages?

Not losslessly in Deckle. You can convert the TIFF with TIFF to PDF and export pages with PDF to PNG, but the pages pass through the quality-90 JPEG step. For exact pixels, save each frame as PNG in an image editor.

Which should I pick in my scanner software?

Pick TIFF for multi-page documents and archives, and PNG for single pages that must open anywhere. If PDF is offered and you only need a PDF, pick that.

Related tools

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