TIFF files
Tagged Image File Format (abbreviated TIFF) is a file format for mainly storing images, including photographs and line art. ... TIFF is a flexible and adaptable file format. It can handle multiple images and data in a single file through the inclusion of "tags" in the file header. Tags can indicate the basic geometry of the image, such as its size, or define how the image data is arranged and whether various image compression options are used. Wikipedia
.Despite TIFF is a very flexible file format, microscope manufactures very frequently implement their own non-standard variants. The Huygens Software tries to read the most popular ones as detailed in File Formats.
A TIFF file can contain a single image or several ones, in which case is called a multidirectory TIFF. This is useful to store a whole 3D stack in a single file, for example.
Important for Ratiometric Images: see Tiff Scaling.