The
Tagged Image File Format (TIFF) was created as the
industry standard for image file storage and transfer,
in order to overcome the problems created by the large
number of proprietary image formats that had been developed.
Created by Aldus, the rights to the format
were originally held by Aldus before the company merged
with Adobe, but although Adobe still owns the copyright
in the specification, the TIFF format has become a
public domain raster file format.
TIFF files were designed to be
independent of the operating system and platform
on which the file is viewed. The TIFF format has
been revised over the years to offer a number of
TIFF options, including a range of compression types,
such as TIFF Raw Uncompressed, TIFF PackBits, LZW
TIFF (using ‘Lempel-Ziv-Welch’ technology),
TIFF CCIT Fax 3 & 4, and even TIFF JPEG,
or ‘JPEG-in-TIFF’ as it’s also known.
TIFF files need to be sufficiently
flexible for use in many different environments. TIFFs
are made up of three parts, or ‘structures’ – the
first of which is the Image File Header (IFH), which
indicates the byte-ordering used in the generation
of the TIFF file (to allow for the variation between
platforms and their image handling). The second part
of the TIFF image file is the Image File Directory
(IFD) which indicates and defines the location within
the TIFF file of the image data or ‘Directory
Entry’ itself, and Multipage TIFF files contain
multiple Image File Directories.
Inside the Directory Entry can
be found the ‘tags’ from
which the TIFF format derives its name. It is these
tags which ensure the longevity of the TIFF format
as the tags can be updated to prevent obsolescence.
TIFFs can be bi-level
(monochrome) called TIFF B, grayscale (called TIFF
G), palette colour (called TIFF P), and RGB colour (TIFF
R). Then there’s also TIFF X which combines all
four colour formats. Often those scanning will only
want to store images in the smaller bi-level or grayscale
TIFF formats as colour isn’t required for the
saved document, which substantially reduces the storage
requirement.
TIFF viewers such as Daeja's ViewONE and ViewONE
Pro decompress and render the image data within
the TIFF files to the screen. ViewONE and ViewONE
Pro do so very quickly.
The complexity of the TIFF
file (and the subsequent size of TIFFs) means that
other image formats specializing in compression with
apparent loss of quality are competing with TIFF
to be the image format standard for the future.
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