ISO/IEC 8859-1

ISO/IEC 8859-1:1998, Information technology — 8-bit single-byte coded graphic character sets — Part 1: Latin alphabet No. 1, is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 1987. ISO 8859-1 encodes what it refers to as "Latin alphabet no. 1," consisting of 191 characters from the Latin script. This character-encoding scheme is used throughout the Americas, Western Europe, Oceania, and much of Africa. It is also commonly used in most standard romanizations of East-Asian languages. It is the basis for most popular 8-bit character sets, including Windows-1252 and the first block of characters in Unicode.

It is very common (on the Internet) to mislabel Windows-1252 text with the charset label ISO-8859-1. A common result was that all the quotes and apostrophes (produced by "smart quotes" in word-processing software) were replaced with question marks or boxes on non-Windows operating systems, making text difficult to read. Most modern web browsers and e-mail clients treat the media type charset ISO-8859-1 as Windows-1252 to accommodate such mislabeling. This is now standard behavior in the HTML5 specification, which requires that documents advertised as ISO-8859-1 actually be parsed with the Windows-1252 encoding.^[1]

As of May 2017, 5.1% of all web sites claim to use ISO 8859-1 (see Windows-1252 for claimed use statistics for both encodings).^[2][3] However, this includes an unknown number of pages actually using Windows-1252 and/or UTF-8, both of which are commonly recognized by browsers despite the character set tag.

ISO-8859-1 is the IANA preferred name for this standard when supplemented with the C0 and C1 control codes from ISO/IEC 6429 (see below for HTML5 exception). IBM calls it Code page 819 or CP819. The following other aliases are registered for ISO-8859-1: iso-ir-100, csISOLatin1, latin1, l1, IBM819. Oracle calls it WE8ISO8859P1.^[4]

The Windows-1252 codepage coincides with ISO-8859-1 for all codes except the range 128 to 159 (hex 80 to 9F), where the little-used C1 controls are replaced with additional characters including all the missing characters provided by ISO-8859-15. Code page 28591 a.k.a. Windows-28591 is the actual ISO-8859-1 codepage.^[5]

Coverage

Each character is encoded as a single eight-bit code value. These code values can be used in almost any data interchange system to communicate in the following languages (with a few exceptions due to missing characters, as noted):

Modern languages with complete coverage

Notes

Languages with incomplete coverage

ISO-8859-1 is commonly used for certain languages, even though it lacks characters used by these languages. In most cases, only a few letters are missing, and they can be replaced with characters that are in ISO-8859-1 using some form of typographic approximation. The following table lists such languages.

The letter ÿ, which appears in French only very rarely, and never at the beginning of words, is included only in lowercase form. The slot corresponding to its uppercase form is occupied by the lowercase letter ß from the German language, which itself is rarely used in its uppercase form.

In rare cases older publishing systems still use ISO-8859-1 encoding with substituted national typeface. Such nonstandard configuration is not noticeable in printed material but leads to serious implications, like impossibility of direct text search, when the material is distributed in electronic form. The most notable are scientific publications in Russian, like those from the publisher Nauka.

Quotation marks

For some languages listed above, the correct typographical quotation marks are missing, as only « », " ", and ' ' are included. Also, this scheme does not provide for oriented (6- or 9-shaped) single or double quotation marks. Some fonts will display the spacing grave accent (0x60) and the apostrophe (0x27) as a matching pair of oriented single quotation marks, but this is not considered part of the modern standard.

History

ISO 8859-1 was based on the Multinational Character Set used by Digital Equipment Corporation (DEC) in the popular VT220 terminal in 1983. It was developed within ECMA, the European Computer Manufacturers Association, and published in March 1985 as ECMA-94,^[6] by which name it is still sometimes known. The second edition of ECMA-94 (June 1986)^[7] also included ISO 8859-2, ISO 8859-3, and ISO 8859-4 as part of the specification.

In 1985, Commodore adopted ECMA-94 for its new AmigaOS operating system.^[8] The Seikosha MP-1300AI impact dot-matrix printer, used with the Amiga 1000, included this encoding.

In 1992, the IANA registered the character map ISO_8859-1:1987, more commonly known by its preferred MIME name of ISO-8859-1 (note the extra hyphen over ISO 8859-1), a superset of ISO 8859-1, for use on the Internet. This map assigns the C0 and C1 control characters to the unassigned code values thus provides for 256 characters via every possible 8-bit value.

ISO-8859-1 is (according to the standards at least) the default encoding of documents delivered via HTTP with a MIME type beginning with "text/" (however the HTML5 specification requires that documents advertised as ISO-8859-1 actually be parsed with the Windows-1252 encoding).^[9][10] It is the default encoding of the values of certain descriptive HTTP headers, and defines the repertoire of characters allowed in HTML 3.2 documents (HTML 4.0, however, is based on Unicode). It and Windows-1252 are often assumed to be the encoding of text on Unix and Microsoft Windows in the absence of locale or other information, this is only gradually being replaced with Unicode encoding such as UTF-8 or UTF-16.

Codepage layout

The two boxed codepoints 215 (0xD7) and 247 (0xF7) were still undefined in the first release of ECMA-94 (1985).^[6]

Legend:

Similar character sets

ISO-8859-1 was incorporated as the first 256 code points of ISO/IEC 10646 and Unicode.

The lower range 32 to 126 (hex 20 to 7E, the G0 subset) maps exactly to the same coded G0 subset of the ISO 646 US variant (commonly known as ASCII), whose ISO 2022 standard switch sequence is "ESC ( B". The higher range 160 to 255 (hex A0 to FF, the G1 subset) maps exactly to the same subset initiated by the ISO 2022 standard switch sequence "ESC . A".

ISO/IEC 8859-1 is missing some characters for French and Finnish text and the euro sign. In order to provide some of these characters, ISO/IEC 8859-15 was developed in 1999 as an update of ISO/IEC 8859-1. Ironically, three of these characters (Œ, œ, and Ÿ) had already been present in the predecessor to ISO/IEC 8859-1 (1987) and ECMA-94 (1985), DEC's Multinational Character Set (MCS) in 1983. Since their original codepoints were now reused for other purposes, the characters had to be reintroduced under different, less logical codepoints. This required the removal of some infrequently used characters from ISO/IEC 8859-1, including fraction symbols and letter-free diacritics: ¤, ¦, ¨, ´, ¸, ¼, ½, and ¾.

The popular Windows-1252 character set adds all the missing characters provided by ISO/IEC 8859-15, plus a number of typographic symbols, by replacing the rarely used C1 controls in the range 128 to 159 (hex 80 to 9F). It is very common to mislabel text data with the charset label ISO-8859-1, even though the data is really Windows-1252 encoded. Many web browsers and e-mail clients will interpret ISO-8859-1 control codes as Windows-1252 characters, and that behavior was later standardized in HTML5,^[11] in order to accommodate such mislabeling and care should be taken to avoid generating these characters in ISO-8859-1 labeled content.

The Apple Macintosh computer introduced a character encoding called Mac Roman, or Mac-Roman, in 1984. It was meant to be suitable for Western European desktop publishing. It is a superset of ASCII, like ISO-8859-1, and has most of the characters that are in ISO-8859-1 but in a totally different arrangement. A later version, registered with IANA as "Macintosh", replaced the generic currency sign ¤ with the euro sign €. The few printable characters that are in ISO 8859-1 but not in this set are often a source of trouble when editing text on websites using older Macintosh browsers (including the last version of Internet Explorer for Mac). However the extra characters that Windows-1252 has in the C1 codepoint range are all supported in MacRoman.

DOS had code page 850, which had all printable characters that ISO-8859-1 had (albeit in a totally different arrangement) plus the most widely used graphic characters from code page 437.

Between 1989^[12] and 2015 Hewlett-Packard used another superset of ISO-8859-1 on many of their calculators. This proprietary character set was sometimes referred to simply as "ECMA-94" as well.^[12]

See also

• Latin script in Unicode
• Unicode
• Universal Character Set
• UTF-8
• Windows code pages
• ISO/IEC JTC 1/SC 2

References

External links

• ISO/IEC 8859-1:1998
• ISO/IEC 8859-1:1998 - 8-bit single-byte coded graphic character sets, Part 1: Latin alphabet No. 1 (draft dated February 12, 1998, published April 15, 1998)
• Standard ECMA-94: 8-Bit Single Byte Coded Graphic Character Sets - Latin Alphabets No. 1 to No. 4 2nd edition (June 1986)
• ISO-IR 100 Right-Hand Part of Latin Alphabet No.1 (February 1, 1986)
• Windows Code pages
• Differences between ANSI, ISO-8859-1 and MacRoman Character Sets
• The Letter Database
• Czyborra, Roman (1998-12-01). "The ISO 8859 Alphabet Soup". Archived from the original on 2016-12-01. Retrieved 2016-12-01.