.tiff, or Tagged Image File Format, is a raster interchange format that was originally designed to be a common format generated by scanners and used by printers.

It can support multiple color spaces, and even layers.

Changed in version 5.1: If build with libtiff 4.2 or later, Krita can open and save Photoshop style layered .tiff. These are different from regular layered .tiff, as Photoshop stores *.psd data inside the .tiff. This means things like layerstyles and blending modes can be stored and read by Photoshop, but not every software that can open layered .tiff will be able to open these.

As an interchange format, .tiff is not meant for sharing on the internet, and you will not find many websites that do accept it. However, printhouses know the file format, and will likely accept it.