Tagged Image File Format

Image File Format – format for storing raster images. Tagged login Originally developed by Aldus, in collaboration with Microsoft for use with PostScript. TIFF has become a popular format for storing images with high color depth. It is used in scanning, faxing, OCR, in printing, is widely supported graphics applications. TIFF was chosen as the primary graphics format NeXTStep operating system and from the support of the format switched to Mac OS X. The company is the owner of specifications – Aldus Corporation – later merged with Adobe, now owns the copyright to these specifications.

File formats TIFF, usually have the extension. Tiff or. Tif.
The signature and the file header

The file header contains a signature and a link (offset) to the first substantial block of data in the file.


A signature file (magic number) TIFF consists of two parts:

Bytes 0-1 – to determine the byte order (represented by the code number system shestandtsaterichnoy and in text-based encoding ASCII):
49 49 («« II »») – in direct (little-endian) byte order, from the name brand processors Intel, using this procedure (see, for example, Intel x86)
4D 4D («MM») – in the opposite (big-endian) byte order, from the name brand processors Motorola, have used this order (see, eg, Motorola 680×0)
Bytes 2-3 – The ID format TIFF (42 – to standard TIFF, 43 – to BigTIFF 64-bit addressing), can be controlled by bytes 0-1):
2A 00 – with a little endian
00 2A – in reverse order of bytes

Thus, there are two possible signatures (depending on byte order):

49 49 2A 00 – with a little endian
4D 4D 00 2A – in reverse order of bytes

Further, bytes 4-7 specify an offset in bytes from the beginning of the file (-aligned WORD (machine word)) in the first IFD directory

TaggedLogin Flexible options

TIFF is a flexible options, adaptive image processing and data file using header from taggedlogin tags (size, definition, image, location data, the compression applied to the image), which determine the geometry of the image. For example, a TIFF file, a vessel with a compressed (lossy) and JPEG (lossless) compressed images PackBits. TIFF file can also vector clipping path (shape, outcrops, picture frames). His ability to save data without any loss in TIFF files of images, it makes sense, because in contrast to the standard JPEG, TIFF with lossless compression (or not) can be edited and saved again without loss of quality image. This is not the case when using the TIFF as a JPEG compressed air tank. Other options TIFF layers and pages.

TIFF offers the option of LZW compression without loss of data compression technology to use in order to reduce the file size. Until 2004, limited the use of this option, because the LZW technique has several patents. However, these patents.


TIFF 6.0 is as follows: [8]

Introduction (includes information on TIFF management, use of private fields and values, etc.)
Part 1: TIFF
Part 2: TIFF Extensions
Part 3: Applications

[Edit] Part 1: TIFF

If the TIFF was introduced, its extensibility led to avoid compatibility problems. Flexibility in coding generates a joke, TIFF supports thousands of incompatible file formats. [9] To avoid these problems, which should each TIFF TIFF reader to read the base. Baseline TIFF does not contain layers or JPEG or LZW compression.

TIFF: Formally known as Baseline TIFF, TIFF 6.0, Part 1. Below is a partial list of the basic functions needed TIFF: [8]
[Citation needed] Several subfiles

TIFF readers must be created for multiple images / multi-page (subfiles) a TIFF file, although it has nothing to do with the images of the first.

There may be more of an image file directory (IFD) to TIFF file format. Each IFD defines a subfile. One of the possible use of part files is used to describe with pictures, like the pages of fax documents. Baseline TIFF reader is not forced to read the IFD is the first [8].
[Edit] Compression

Baseline TIFF readers must handle the following three compression techniques [8]

Uncompressed
CCITT Group 3 1-dimensional modified Huffman RLE
PackBits compression – a form of run-length coding

[Edit] Types of images

Basic types of TIFF images. Two levels, grayscale palette of colors and RGB color images [8]
[Edit] to byte

Each TIFF begins with a rate of about 2 bytes of bytes: “II” for little endian and “MM” for big-endian byte. The next two bytes represent the number 42, chosen because it is a binary number 101 010 and a “deep philosophical meaning” (just kidding). [10], 42-byte read is specified by the order by the indicator is 2 bytes. All of these words, double words and etc., in a TIFF file in the order of bytes. TIFF 6.0 specification says that the TIFF reader must support both byte orders support (II and MM). Writers can use any of [11]
[Edit] Other areas TIFF

TIFF readers must be willing to find, and ignore the private fields that are not described in the TIFF specification. TIFF readers must not stop reading the TIFF file, although there are some optional fields [8].
[Edit] Part 2: TIFF Extensions

Many readers with TIFF tags, in addition to the basics in TIFF, but not all readers support all extensions. [12] [13] [14] [15] As a result, Baseline TIFF has become functions of the lowest common denominator TIFF format. Basic features expanded TIFF TIFF extensions (defined in the TIFF 6.0 specifications Part 2), but extensions can be defined in the Private label.

TIFF extensions: TIFF extensions is officially known as TIFF 6.0, part 2. Here are some examples of extensions to TIFF TIFF 6.0 specification defines [8]

CCITT T.4 bi-level coding
CCITT T.6 bi-level coding
LZW compression
JPEG compression scheme
CMYK Image
YCbCr images
HalftoneHints
The tiled images
CIE L * A * B * Images

Many use the uncompressed TIFF image is only 32-bit RGB or CMYK contains 24-bit images [Edit].

After the TIFF 6.0 specification (Introduction), all TIFF files with TIFF proposed extensions that are not from Adobe as part of TIFF-based (usually specialized use TIFF, which was approved at the autumn publishing or general graphics and image exchange) should be called or TIFF files should not in any way be confused with core files from TIFF to be marked.