| Filename extension | .tiff, .tif |
|---|---|
| Internet media type | image/tiff, image/tiff-fx |
| Type code | TIFF |
| Uniform Type Identifier | public.tiff |
| Developed by | Aldus, now Adobe Systems |
| Initial release | 1986 |
| Latest release | TIFF 6.0 / 3 June 1992 TIFF Supplement 2 / 22 March 2002 |
| Type of format | Image file format |
| Extended to | Exif, DCF, TIFF/EP, TIFF/IT, TIFF-FX, GeoTIFF |
TIFF (originally standing for Tagged Image File Format) is a file format for storing images, popular among graphic artists, the publishing industry,[1] and both amateur and professional photographers in general. As of 2009, it is under the control of Adobe Systems. Originally created by the company Aldus[2] for use with what was then called "desktop publishing", the TIFF format is widely supported by image-manipulation applications, by publishing and page layout applications, by scanning, faxing, word processing, optical character recognition and other applications.[3] Adobe Systems, which acquired Aldus, now holds the copyright to the TIFF specification. TIFF has not had a major update since 1992, though several Aldus/Adobe technical notes have been published with minor extensions to the format, and several specifications, including TIFF/EP (ISO 12234-2), TIFF/IT (ISO 12639),[4][5][6] TIFF-F (RFC 2306) and TIFF-FX (RFC 3949)[7] have been based on the TIFF 6.0 specification.
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The phrases "Tagged Image File Format" and "Tag Image File Format" were used as the subtitle to some early versions of the TIFF specification; the 1992 specification, TIFF 6.0, does not use either subtitle phrase, but is simply "TIFF".
TIFF was originally created as an attempt to get desktop scanner vendors of the mid-1980s to agree on a common scanned image file format, rather than have each company promote its own proprietary format. In the beginning, TIFF was only a binary image format (only two possible values for each pixel), because that was all that desktop scanners could handle. As scanners became more powerful, and as desktop computer disk space became more plentiful, TIFF grew to accommodate grayscale images, then color images. Today, TIFF is a popular format for high color-depth images, along with JPEG and PNG.
The first version of the TIFF specification was published by Aldus Corporation in the autumn of 1986 after two major earlier draft releases. It can be labeled as Revision 3.0. It was published after a series of meetings with various scanner manufacturers and software developers. In April 1987 Revision 4.0 was released and it contained mostly minor enhancements. In October 1988 Revision 5.0 was released and it added support for palette color images and LZW compression.[8]
TIFF is a flexible, adaptable file format for handling images and data within a single file, by including the header tags (size, definition, image-data arrangement, applied image compression) defining the image's geometry. For example, a TIFF file can be a container holding compressed (lossy) JPEG and (lossless) PackBits compressed images. A TIFF file also can include a vector-based clipping path (outlines, croppings, image frames). The ability to store image data in a lossless format makes a TIFF file a useful image archive, because, unlike standard JPEG files, a TIFF file using lossless compression (or none) may be edited and re-saved without losing image quality. This is not the case when using the TIFF as a container holding compressed JPEG. Other TIFF options are layers and pages.
TIFF offers the option of using LZW compression, a lossless data-compression technique for reducing a file's size. Until 2004, use of this option was limited because the LZW technique was under several patents. However, these patents have expired.
The TIFF 6.0 specification consists of the following parts:[8]
When TIFF was introduced, its extensibility provoked compatibility problems. The flexibility in encoding gave rise to the joke that TIFF stands for Thousands of Incompatible File Formats.[9] To avoid these problems, every TIFF reader was required to read Baseline TIFF. The Baseline TIFF does not include layers, or compression with JPEG or LZW.
The Baseline TIFF is formally known as TIFF 6.0, Part 1: Baseline TIFF. The following is an incomplete list of required Baseline TIFF features:[8]
TIFF readers must be prepared for multiple/multi-page images (subfiles) per TIFF file, although they are not required to do anything with images after the first one.
There may be more than one Image File Directory (IFD) in a TIFF file. Each IFD defines a subfile. One potential use of subfiles is to describe related images, such as the pages of a facsimile document. A Baseline TIFF reader is not required to read any IFD beyond the first one.[8]
Baseline TIFF readers must handle the following three compression schemes:[8]
Baseline TIFF image types are: bilevel, grayscale, palette-color, and RGB full-color images.[8]
Every TIFF begins with a 2-byte indicator of byte order: "II" for little-endian and "MM" for big-endian byte ordering. The next 2 bytes represent the number 42, selected because this is the binary pattern 101010 and "for its deep philosophical significance".[10] The 42-reading depends upon the byte order indicated by the 2-byte indicator. All words, double words, etc., in the TIFF file are assumed to be in the indicated byte order. The TIFF 6.0 specification says that compliant TIFF readers must support both byte orders (II and MM); writers may use either.[11]
TIFF readers must be prepared to encounter and ignore private fields not described in the TIFF specification. TIFF readers must not refuse to read a TIFF file if some optional fields do not exist.[8]
Many TIFF readers support tags additional to those in Baseline TIFF, but not every reader supports every extension.[12][13][14][15] As a consequence, Baseline TIFF features became the lowest common denominator for TIFF format. Baseline TIFF features are extended in TIFF Extensions (defined in the TIFF 6.0 Part 2 specification) but extensions can also be defined in private tags.
The TIFF Extensions are formally known as TIFF 6.0, Part 2: TIFF Extensions. Here are some examples of TIFF extensions defined in TIFF 6.0 specification:[8]
Many used TIFF images contain only uncompressed 32-bit CMYK or 24-bit RGB images.
According to TIFF 6.0 specification (Introduction), all TIFF files using proposed TIFF extensions that are not approved by Adobe as part of Baseline TIFF (typically for specialized uses of TIFF that do not fall within the domain of publishing or general graphics or picture interchange) should be either not called TIFF files or should be marked some way so that they will not be confused with mainstream TIFF files.
Developers can apply for a block of "private tags" to enable them to include their own proprietary information inside a TIFF file without causing problems for file interchange. TIFF readers are required to ignore tags that they do not recognize, and a registered developer's private tags are guaranteed not to clash with anyone else's tags or with the standard set of tags defined in the specification.
TIFF Tags numbered 32768 or higher, sometimes called private tags, are reserved for information meaningful only for some organization or for experiments with a new compression scheme within TIFF. Upon request, the TIFF administrator (Adobe) will allocate and register one or more private tags for an organization, to avoid possible conflicts with other organizations. Organizations and developers are discouraged from choosing their own tag numbers, because doing so could cause serious compatibility problems. However, if there is little or no chance that TIFF files will escape a private environment, organizations and developers are encouraged to consider using TIFF tags in the "reusable" 65000-65535 range. There is no need to contact Adobe when using numbers in this range.[8]
The image/tiff MIME type (defined in RFC 3302) without an application parameter is used for Baseline TIFF 6.0 files or to indicate that it is not necessary to identify a specific subset of TIFF or TIFF extensions. The optional "application" parameter (Example: Content-type: image/tiff; application=foo) is defined for image/tiff to identify a particular subset of TIFF and TIFF extensions for the encoded image data, if it is known. According to RFC 3302, specific TIFF subsets or TIFF extensions used in the application parameter must be published as an RFC.[16]
The TIFF Tag 259 (hex 0x0103) stores the information about the Compression method. The default value is 1 = no compression.
Most of TIFF writers and TIFF readers support only some of existing TIFF compression schemes. Here are some examples of used TIFF compression schemes:
| Tag value | Compression scheme | Lossy/lossless | Specification | Description | Type of images | Usage and support |
|---|---|---|---|---|---|---|
| 1 | Uncompressed | Lossless | TIFF 6.0 | Baseline TIFF | all | common |
| 2 | CCITT Group 3 1-Dimensional Modified Huffman run length encoding (a.k.a. MH or CCITT 1D) | Lossless | TIFF 6.0 | Baseline TIFF; compression based on ITU-T T.4 | black and white | common |
| 32773 | PackBits compression, a.k.a. Macintosh RLE | Lossless | TIFF 6.0 | Baseline TIFF | all | common |
| 3 | CCITT T.4 bi-level encoding as specified in section 4, Coding, of ITU-T Recommendation T.4 (a.k.a. CCITT Group 3 fax encoding or CCITT Group 3 2D) | Lossless | TIFF 6.0 | TIFF 6.0 Extensions; compression based on ITU-T T.4 | black and white | common |
| 4 | CCITT T.6 bi-level encoding as specified in section 2 of ITU-T Recommendation T.6 (a.k.a. CCITT Group 4 fax encoding) | Lossless | TIFF 6.0 | TIFF 6.0 extensions; compression based on ITU-T T.6 | black and white | common |
| 5 | LZW (Lempel-Ziv & Welch algorithm) | Lossless | TIFF 6.0 | TIFF 6.0 Extensions; first defined in TIFF 5 (1988); a patented compression algorithm, but the patents expired in 2003 and 2004 | all | common |
| 6 | JPEG ('old-style' JPEG, later overridden in Technote2) | Lossy | TIFF 6.0 | TIFF 6.0 Extensions; first defined in TIFF 6 (1992) | continuous-tone | rare |
| 7 | JPEG ('new-style' JPEG) | Lossy | TIFF 6 Technote2 (1995) | Technote2 overrides old-style JPEG compression; it is a TIFF 6.0 extension | continuous-tone | medium |
| 32946 | Deflate (PKZIP-style Deflate encoding) (experimental) | Lossless | proprietary | According to TIFF Specification Supplement 2 it should be considered obsolete but reading is recommended | all | medium |
| 8 | Deflate ('Adobe-style') | Lossless | TIFF Specification Supplement 2 (2002) | Adobe Photoshop TIFF Technical Notes; it is a TIFF 6.0 extension | all | medium |
| 9 | JBIG, per ITU-T T.85 | Lossless | TIFF-FX | RFC 2301 (1998), RFC 3949 (2005) | black and white | rare |
| 10 | JBIG, per ITU-T T.43 | Lossless | TIFF-FX | RFC 2301 (1998), RFC 3949 (2005) | black and white | rare |
| 32766 | NeXT RLE 2-bit grey scale encoding | proprietary | rare | |||
| 32809 | ThunderScan RLE 4-bit encoding | proprietary | black and white | rare | ||
| 32895 | RasterPadding in CT or MP (Continuous Tone or Monochrome Picture) | Lossless | TIFF/IT (1998, 2004) | ISO 12639 | rare | |
| 32896 | RLE for LW (Line Work) | Lossless | TIFF/IT (1998, 2004) | ISO 12639 | rare | |
| 32897 | RLE for HC (High-resolution Continuous-tone) | Lossless | TIFF/IT (1998, 2004) | ISO 12639 | rare | |
| 32898 | RLE for BL (Binary Line work) | Lossless | TIFF/IT (1998, 2004) | ISO 12639 | rare | |
| 32947 | Kodak DCS | proprietary | rare | |||
| 34661 | JBIG | LibTiff | black and white | rare | ||
| 34712 | JPEG2000 | proprietary | Intoduced by Leadtools[25] | rare | ||
| 34713 | Nikon NEF Compressed | proprietary | rare |
The TIFF file formats use 32-bit offsets, which limits file size to 4 GiB (4,294,967,296 bytes). BigTIFF is a TIFF variant file format which uses 64-bit offsets and supports much larger files.[26] The BigTIFF file format specification was implemented in 2007 in development releases of LibTIFF version 4.0, which as of July 2011[update] is still in beta development. Support for BigTIFF file formats by applications is limited.
Adobe holds the copyright on the TIFF specification (aka TIFF 6.0) along with the two supplements that have been published. All of these documents can be found on the Adobe TIFF Resources page. TIFF specification has not been standardized by either ISO or ANSI, but other standards based on TIFF specification were standardized. Various TIFF variations have been used by organizations for numerous years.
TIFF files that strictly use the basic "tag sets" as defined in TIFF 6.0 along with restricting the compression technology to the methods identified in TIFF 6.0 and are adequately tested and verified by multiple sources for all documents being created can be used for storing documents. Commonly seen issues encountered in the content and document management industry associated with the use of TIFF files arise when the structures contain proprietary headers, are not properly documented, and/or contain "wrappers" or other containers around the TIFF datasets, and/or include improper compression technologies, or those compression technologies are not properly implemented.
Variants of the TIFF format can be used within document imaging and content/document management systems using CCITT Group IV 2D compression which supports black-and-white (bitonal, monochrome) images, among other compression technologies that support color. When storage capacity and network bandwidth was a greater issue than commonly seen in today's server environments, high-volume storage scanning, documents were scanned in black and white (not in color or in grayscale) to conserve storage capacity. An average A4 scanning produces 30 kB of data at 200 PPI (pixels per inch of resolution) and 50 kB of data at 300 PPI; 300 PPI is more common than 200 PPI.
The TIFF format can save multi-page documents to a single TIFF file rather than a series of files for each scanned page. Multi-page support and 2D compression of bitonal images led to TIFF's becoming the widely accepted format for facsimiles, especially on Fax Servers.
The inclusion of the SampleFormat tag in TIFF 6.0 allows TIFF files to handle advanced pixel data types, including integer images with more than 8 bits per channel and floating point images. This tag made TIFF 6.0 a viable format for scientific image processing where extended precision is required. An example would be the use of TIFF to store images acquired using scientific CCD cameras that provide up to 16 bits per photosite of intensity resolution. Storing a sequence of images in a single TIFF file is also possible, and is allowed under TIFF 6.0, provided the rules for multi-page images are followed.
In many cases TIFF has been superseded by FITS files for scientific applications (for example astronomical data).
| Filename extension | .fp, .ct, .lw, .hc, .mp, .bp, .bl, .sd[16] |
|---|---|
| Internet media type | not defined[16] |
| Developed by | ANSI, ISO |
| Initial release | 1993 |
| Latest release | TIFF/IT / 2004 |
| Type of format | Image file format |
| Extended from | TIFF 6.0 |
| Standard(s) | ISO 12639[4][27][28] |
TIFF/IT is a file format structured to digitally send data for print ready pages that have been created on high-end prepress systems.[29] The TIFF/IT specification (ISO 12639) describes a multiple-file format which can describe a single page per file set.[30] TIFF/IT files are different from common TIFF files and they are not interchangeable.[31][32][33]
The goals in developing TIFF/IT were to carry forward the original IT8 magnetic tape formats into a media independent version. TIFF/IT is based on Adobe TIFF 6.0 specification and both extends TIFF 6 by adding additional tags and restricts it by limiting some tags and the values within tags. Not all valid TIFF/IT images are valid TIFF 6.0 images.[34]
TIFF/IT defines image file formats for encoding colour continuous tone picture images, colour line art images, high resolution continuous tone images, monochrome continuous tone images, binary picture images, binary line art images, screened data, and images of composite final pages.[5]
TIFF/IT consists of a number of different files and it cannot be created or opened by common desktop applications.[16][31][35] TIFF/IT-P1 file sets usually consist of the following files:[5][6][36]
TIFF/IT also defines the following files:[5]
Some of these data types are partly compatible with the corresponding definitions in the TIFF 6.0 specification. The Final Page (FP) allows the various files needed to define a complete page to be grouped together - it provides a mechanism for creating a package that includes separate image layers (of types CT, LW, etc.) to be combined to create the final printed image. Its use is recommended but not required. There must be at least one subfile in an FP file, but no more than one of each type. It typically contains a CT subfile and an LW subfile.[5][34][37]
The primary color space for this standard is CMYK, but also other color spaces and the use of ICC Profiles are supported.[5]
TIFF/IT makes no provision for compression within the file structure itself, but there are no restrictions.[34] (For example, it is allowed to compress the whole file structure in a ZIP archive.) LW files use a specific compression scheme known as Run-length encoding for LW (Compression tag value is 32896). HC files also use a specific Run-length encoding for HC (Compression tag value is 32897). The TIFF/IT P1 specs do not allow use of compression within the CT file.
The following is a list of defined TIFF/IT compression schemes:[28]
| File type | TIFF/IT conformance | TIFF/IT-P1 conformance | TIFF/IT-P2 conformance | Description |
|---|---|---|---|---|
| Final Page (FP) 0th IFD field | Uncompressed (1), Deflate (8) or PackBits (32773) | Uncompressed (1), Deflate (8) or PackBits (32773) | Uncompressed (1), Deflate (8) or PackBits (32773) | |
| Continuous Tone (CT) | Uncompressed (1), JPEG (7), Deflate (8) or RasterPadding in CT or MP (32895) | Uncompressed (1) | Uncompressed (1), JPEG (7), Deflate (8) | |
| Line Work (LW) | RLE for LW (32896) | RLE for LW (32896) | RLE for LW (32896) | |
| High resolution Continuous tone (HC) | RLE for HC (32897) | RLE for HC (32897) | RLE for HC (32897) | |
| Monochrome continuous-tone Picture (MP) | Uncompressed (1), JPEG (7), Deflate (8) or RasterPadding in CT or MP (32895) | Uncompressed (1) | Uncompressed (1), JPEG (7), Deflate (8) | |
| Binary Picture images (BP) | Uncompressed (1), CCITT T.6 bi-level encoding (4), Deflate (8) | Uncompressed (1) | Uncompressed (1), CCITT T.6 bi-level encoding (4), Deflate (8) | |
| Binary Line art (BL) | RLE for BL (32898) | RLE for BL (32898) | ||
| Screened Data (SD) | Uncompressed (1), CCITT T.6 bi-level encoding (4), Deflate (8) | Uncompressed (1), CCITT T.6 bi-level encoding (4), Deflate (8) |
There is no MIME type defined for TIFF/IT. The image/tiff MIME type should not be used for TIFF/IT files, because TIFF/IT does not conform to Baseline TIFF 6.0 and the widely-deployed TIFF 6.0 readers are not able to read TIFF/IT. The image/tiff MIME type (defined in RFC 3302) without an application parameter is used for Baseline TIFF 6.0 files or to indicate that it is not necessary to identify a specific subset of TIFF or TIFF extensions. The application parameter should be used with the image/tiff to distinguish TIFF extensions or TIFF subsets. According to RFC 3302, specific TIFF subsets or TIFF extensions must be published as an RFC. There is no such an RFC for TIFF/IT. There is also no plan by the ISO committee that oversees TIFF/IT standard to register TIFF/IT with either a parameter to image/tiff or as new separate MIME type.[16]
The ISO 12639:1998 introduced TIFF/IT-P1 (Profile 1) - a direct subset of the full TIFF/IT standard (previously defined in ANSI IT8.8–1993). This subset was developed on the ground of the mutual realization by both the standards and the software development communities that an implementation of the full TIFF/IT standard by any one vendor was both unlikely (because of its complexity), and unnecessary (because Profile 1 would cover most applications for digital ad delivery). Almost all TIFF/IT files in digital advertising were distributed as TIFF/IT-P1 file sets in 2001.[38][39] When people talk about TIFF/IT, they usually mean the P1 standard.[6]
Here are some of the restrictions on TIFF/IT-P1 (compared to TIFF/IT):[37]
TIFF/IT-P1 is a simplified conformance level of TIFF/IT and it maximizes the compatibility between Color Electronic Prepress Systems (CEPS) and Desk Top Publishing (DTP) worlds.[34][40] It provides a clean interface for the proprietary CEPS formats such as the Scitex CT/LW format.
Because TIFF/IT P1 had a number of limitations, an extended format was developed. The ISO 12639:2004 introduced a new extended conformance level - TIFF/IT-P2 (Profile 2). TIFF/IT-P2 added a number of functions to TIFF/IT-P1 like:[6]
This format was not widely used.
The TIFF/IT specification preserved the TIFF possibility for developers to utilize private tags. The TIFF/IT specification is very precise regarding how these private tags should be treated - they should be parsed, but ignored.[41]
Private tags in the TIFF/IT-P1 specification were originally intended to provide developers with ways to add specific functionality for specific applications. Private tags can be used by developers (e.g. Scitex) to preserve specific printing values or other functionality. Private tags are typically labelled with tag numbers greater than or equal to 32768.
All private tags must be requested from Adobe (the TIFF administrator) and registered.
In 1992 the DDAP (Digital Distribution of Advertising for Publication, later Digital Directions in Applications for Production) developed their requirement statement for digital ad delivery. This was presented to ANSI-accredited CGATS (Committee for Graphic Arts Technology Standards) for development of an accredited file format standard for the delivery of digital ads. CGATS reviewed their alternatives for this purpose and TIFF format seemed like the ideal candidate, except for the fact that it could not handle certain required functionalities. CGATS asked Aldus (the TIFF administrator) for a block of their own TIFF private tags in order to implement what eventually became TIFF/IT. For example, the ability to identify the sequence of the colors is handled by tag 34017 - the Color Sequence Tag.[41]
TIFF/IT was created to satisfy the need for a transport-independent method of encoding raster data in the IT8.1, IT8.2 and IT8.5 standards.
TIFF/IT was defined in ANSI IT8.8–1993 standard in 1993 and later revised in the International Standard ISO 12639:1998 - Prepress digital data exchange – Tag image file format for image technology (TIFF/IT).[4] The ISO standard replaces ANSI IT8.8–1993. It specifies a media-independent means for prepress electronic data exchange.[42]
The ISO 12639:2004 (Second edition) standard for TIFF/IT superseded the ISO 12639:1998. It was also later extended in ISO 12639:2004 / Amd. 1:2007 - Use of JBIG2-Amd2 compression in TIFF/IT.
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