On scans, PNG is smaller than JPG and loses nothing

This is the rare conversion with no trade to explain. Running a real 1240 by 1754 A4 text scan through it, the 6.22 MB TIFF came out as a 114 KB PNG, 98.2 percent smaller, and mathematically identical to the original at a maximum per pixel error of zero. On the very same file, JPEG needed between 129 KB and 217 KB depending on the level, and introduced errors of up to 79 out of 255 along the edges of the letters.

That result is not a quirk of one file. PNG compresses runs of identical pixels, which is most of what a scanned page or a screenshot is made of, while JPEG spends its bits describing gradual change that documents do not contain.

Every page of a multi-page scan, not just the first

A TIFF from a document scanner often holds the whole stack in one file, and most converters quietly hand back page one. Tick "Convert every page" and each page comes back as its own numbered PNG inside a single ZIP, in order: scan-1.png, scan-2.png, and so on, zero padded to the width of the last page so a twelve page document sorts correctly as scan-01 through scan-12. Leave it off and you get page one, with the page count reported on the result so you know the rest exist. The checkbox only appears when a TIFF is in the selection, because no other format has pages.

16-bit scans come out as images, not blank pages

Film and archive scanners write 16 bits per channel. Read as if it were ordinary 8-bit data, that file turns into a black or white rectangle. Here the samples are rescaled by the bit depth the file itself declares, so 12-bit and 14-bit scanner output lands correctly too, and the result carries a note saying the samples were scaled down. The tonal range is preserved; only the storage depth changes.

Where PNG wins, and where it does not

Scanned documents, screenshots, line art, diagrams, logos, and anything with sharp edges or flat areas of colour all favour PNG. Photographs go the other way. A photographic TIFF converted to a full colour PNG can end up larger than you expect, because lossless compression has very little repetition to work with in a photo. For those files, palette compression is available as a checkbox, and the JPG converter is often the better answer.

Transparency survives intact

PNG has a real alpha channel, so a transparent background in your TIFF is carried across untouched rather than flattened onto white. That is the main reason to pick PNG over JPG for logos, stamps, signatures, and anything that has to sit on top of another image later.

Colour profile and dimensions

The embedded colour profile is preserved by default rather than stripped, which matters for scans calibrated for print, and a single setting converts cleanly to sRGB when you want that instead. The image comes back at exactly the dimensions it went in. Nothing is resized, cropped, or resampled.

What the settings actually do

The compression effort setting only changes how hard the encoder works looking for repetition; it never changes a single pixel. That is why the result is labelled Lossless rather than carrying a quality number, which would mean nothing here. Fast finishes sooner on large scans, Smallest squeezes a little further, and all three produce the same image. Free, no account, no watermark, and finished files are deleted an hour after the conversion.

What you get

• A lossless PNG, our converted scan matched the source TIFF at a maximum per pixel error of 0
• A smaller file than JPEG on scanned text, 114 KB against 129 KB to 217 KB on the same page
• Every page of a multi-page scan as its own numbered PNG, in order, when you ask for it
• 16-bit and 12-bit scanner output rescaled properly instead of coming back blank
• Transparency carried across intact, and the original dimensions and colour profile preserved
• Free, no account, no watermark, and files deleted after one hour

What's next?

For photographic TIFFs, where size matters more than exact pixels, TIFF to JPG gives a much smaller file. To keep the TIFF format and cut the size, use Compress TIFF. For a multi-page scan that has to stay in one file, use TIFF to PDF.