PDF sang TIFF

Công cụ này làm gì

TIFF is not a format anyone picks for pleasure. People arrive here because a court filing system, a medical archive, a records department or a fax gateway will accept nothing else, usually at 300 dpi and often bilevel. So this renders each page at the resolution you set and writes it into a TIFF, by default as one multi-page file rather than a folder of separate ones.

Use it when something on the other end has specified TIFF: an e-filing portal, a document management system that only indexes TIFF, an archive with a retention standard written before PDF existed, or a fax service that takes image files.

Cách hoạt động

1. Drop the PDF onto this page. Files up to 300 MB are accepted, because scans run large.
2. Set the resolution. 300 dpi is what most filing systems ask for; 200 is enough for on-screen review and 600 is for archival capture of fine detail.
3. Choose colour, gray or bilevel. Bilevel is the black-and-white setting those systems usually mean, and it is what keeps the file small.
4. Leave One multi-page file on unless the receiving system genuinely wants a separate image per page.
5. Press Convert to TIFF and download the result.

Bilevel is the setting that decides whether the result is manageable. An A4 page at 300 dpi is about 8.7 million pixels, which is roughly 25 MB of colour data before compression; bilevel packs eight pixels into a single byte and brings the same page down to a little over one megabyte before compression, and to a few hundred kilobytes after it. The polarity is handled correctly, which matters more than it sounds - white has to be zero, and getting that backwards produces a negative of the page.

Pages are rendered to PNG on the way out of the renderer and then re-encoded into the TIFF, rather than passing through JPEG first. That avoids throwing away detail in a lossy step that nobody asked for, which is the sort of quiet quality loss an archival conversion should not contain.

Compression is deflate or none, and nothing else. Deflate is lossless, widely readable and does well on text pages. Group 4 fax compression, which a few older bilevel workflows expect and which would be smaller still, is not written here - if a system rejects the output for that reason, it is the one thing this tool cannot give you.

Rendering happens on your device through PDF.js, and the TIFF is assembled there too. Medical and legal documents are the usual traffic for this converter, so it is worth being explicit: no page image is produced on a server, and nothing about the file is sent anywhere.