Convert TIFF to PDF

Very few people choose TIFF for a photograph. What produces them is scanning: office scanners, document-management systems, records departments, archives, and the software attached to all of them have written TIFF since the 1980s and mostly still do.

So the file at hand is usually paperwork — a signed contract, a set of plans, a medical record, an insurance claim, a court filing. That shapes what a good conversion looks like: nothing needs improving, the pixels must not change, and the result has to be a document that any recipient can open and file.

PDF won the document argument comprehensively. Court filing portals, government upload forms, client extranets, email attachments, contract management systems and every colleague’s laptop expect it, and a good many of them will reject a TIFF outright — no browser displays one, and most people cannot open one at all.

Which means this conversion is rarely about the image and almost always about the container. The scan is fine; the wrapper is the wrong one for where it now has to go.

The picture is written into the PDF without a lossy pass over it. There is no re-scanning, no resampling and no JPEG step, so text stays as crisp as the scanner made it and a signature keeps its thin strokes.

That matters for documents in a way it does not for photographs. A scan already sits close to the edge of legibility on small print and faint stamps, and any additional compression is exactly where a figure becomes ambiguous. A lossless conversion means the PDF is as readable as the scan and no less.

Scanners frequently produce a single multi-page TIFF holding a whole document. This conversion reads the first image in the file and stops there, so a ten-page scan comes back as a one-page PDF and the remaining nine pages are not in it anywhere.

On a single-page document that never shows. On a bundle it is the failure worth checking for, because the PDF looks complete and is not — open it and count the pages before sending it on. Where every page has to survive, they have to be separated before the file gets here: the scanner, the document system that wrote the TIFF, or a tool that splits a multi-page TIFF into one file per page.

A scan is a photograph of a page. The letters are shapes, not characters, so the PDF cannot be searched, the text cannot be copied, and a screen reader has nothing to read. Converting the container does not change that in either direction.

Optical character recognition is what does — it looks at the shapes and works out the letters, adding an invisible text layer behind the image so the page looks identical and becomes searchable. It is a genuinely separate operation with its own error rate, and worth doing deliberately for an archive rather than assuming a format conversion included it.

Scans are usually stored as uncompressed TIFF, because that is the variant every scanner and archive tool reliably reads. An A4 page at 300 dpi is roughly 2480 by 3508 pixels, which is about 35 megabytes; at 150 dpi it is nearer 9.

The PDF inherits that, and no choice in this conversion changes it — the container adds a little structure and nothing else. If the file has to be emailed or uploaded under a size limit, the lever is the scan itself: a lower resolution where the document allows it, or a compression step applied to the images. Zipping helps too, since uncompressed pixel data compresses well.

For a scanned document, choose the paper size it came from — A4 or US Letter — rather than fitting the page to the image. The document then prints correctly, files alongside other paperwork, and looks like what it is.

Fit to image is the better default for pictures and the wrong one for paperwork: it produces a PDF whose page is an odd size determined by the scanner’s pixel dimensions, which prints with unexpected margins and looks out of place in a bundle. A margin is worth setting if the document will be printed, since most printers cannot put ink to the edge of a sheet.

The conversion runs inside the browser tab on your own processor. Nothing is uploaded, so there is no server copy, no retention period to ask about and no account to make; the free ceiling of 100 MB per file is the only limit, and an uncompressed A4 page scanned at 600 dpi in colour is about 104 megabytes on its own.

Given what people scan to TIFF, that is the substantive point rather than a detail. Signed contracts, patient records, case files and claims are exactly the documents where the safest handling is the kind where the file never travels.