PNG vs TIFF

Neither format discards anything. A photograph saved as a PNG and the same photograph saved as a TIFF contain identical pixels, and converting between them in either direction changes nothing about the image. Anyone told that TIFF is "higher quality" has been told something that is not true.

What differs is what surrounds the pixels: how large the file is, what extra information it can carry, and which industries built their workflows around it. That is what this comparison is actually about.

PNG compresses, losslessly and quite well. TIFF very often does not — the baseline uncompressed variant stores every pixel as plain bytes, which is what makes it universally readable and what makes it enormous.

A 2000 by 2000 image is roughly 16 megabytes as an uncompressed TIFF regardless of what it contains, where the PNG of a flat graphic might be a few kilobytes and of a photograph a few megabytes. TIFF does support compression schemes, and they are exactly where elderly print and archive software starts refusing files, which is why the uncompressed form persists.

Several pages in one file, which is why scanners produce multi-page TIFFs of documents. Layers, in the variant Photoshop writes. CMYK colour, which matters for commercial printing where PNG only speaks RGB. Sixteen bits per channel with full colour-management data. Embedded colour profiles that print workflows depend on, and rich metadata including the scanning device and its settings.

PNG has none of this and never intended to. It was designed in 1996 to be a good image format for the web and for interface graphics — one page, RGB, small, and simple enough that every browser could implement it correctly. It succeeded at that and did not try to become a production format.

Commercial printers and pre-press, whose workflows were built around it before PDF took over and who still accept it. Document management and records systems in law, insurance and healthcare. Scanning software, which has written TIFF since the 1980s. Archives, museums and libraries, where it is frequently the specified preservation format. Scientific and medical imaging, where the bit depth and metadata are the point.

What these have in common is that somebody wrote a specification naming the format, and nothing since has been worth the cost of changing it. TIFF is not chosen for convenience; it is chosen because a requirement says so.

Everyone else. Anything on a web page, in an email, in a document, in a presentation, uploaded to a form, or handed to a colleague. PNG holds the same pixels in a fraction of the space and opens in every program made this century, including on a phone.

The transparency case is worth naming separately: PNG has a proper alpha channel and it works everywhere. TIFF can carry alpha too, and a number of print workflows and older tools ignore it and composite onto white — so a cut-out image is safer as a PNG in every context that is not specifically demanding TIFF.

PNG to TIFF is a container change with no visual consequence at all, done because a specification asks for it. Expect the file to grow considerably, expect the alpha channel to survive in the file and possibly be ignored by the recipient, and expect no improvement in quality — there is none available.

TIFF to PNG is the more useful direction and equally lossless, provided the TIFF is a single page in RGB at eight bits. A multi-page TIFF becomes one PNG per page; a CMYK TIFF has to be converted to RGB, which is a genuine colour transformation and not merely a re-wrap; and sixteen-bit data is reduced unless the tool preserves it.

Safari displays TIFF and no other browser does, so it never was. PNG is, and for interface graphics it remains the safe fallback — but WebP is smaller by a quarter to a half with nothing given up, and every current browser reads it.

The sensible arrangement is TIFF only when a specification names it, PNG as the universal exchange and fallback format, and WebP or AVIF as what a site actually serves. Keeping a PNG or TIFF master and generating the web formats from it is the same discipline as keeping a lossless audio master, and for the same reason.