PNG to TIFF Converter

PNG is the web's lossless format; TIFF is the lossless format of printing, publishing, scanning and archiving. Both keep every pixel, so converting is lossless — but TIFF adds a recorded print resolution, several compression choices and multi-page files that layout, prepress and document systems expect. This converter keeps PNG transparency as a true alpha channel (or flattens it on white or black) and runs entirely in your browser.

How to use this tool

1. Drop one or more PNG files.
2. Keep transparency as an alpha channel, or flatten it on white for printing.
3. Choose LZW, Deflate or no compression, and keep the PNG's stored resolution or set one such as 300 DPI.
4. Optionally combine the images into one multi-page TIFF, then download.

Formula

TIFF = 8-byte header ("II", 42, first IFD offset) + per page an image file directory (ImageWidth, ImageLength, BitsPerSample 8,8,8[,8], Compression, Photometric RGB, StripOffsets, SamplesPerPixel, RowsPerStrip, StripByteCounts, X/YResolution, ResolutionUnit, ExtraSamples for alpha) + ~64 KB strips.

Alpha is stored unassociated (ExtraSamples = 2), the same as PNG, so colours of semi-transparent pixels are not premultiplied. LZW and Deflate are lossless and use predictor 2. A PNG pHYs resolution is kept when you choose "Keep"; otherwise 72 DPI is written. 16-bit PNGs are saved with 8 bits per channel.

Example

An opaque 160 × 100 PNG saved without compression is exactly 48,192 bytes: 8 bytes of header, a 162-byte directory with 13 tags, 22 bytes of tag values and 48,000 bytes of pixels. With transparency kept, the page gains a 4th channel and an ExtraSamples tag: 8 + 174 + 24 + 64,000 = 64,206 bytes.