Register of public PNG chunks and keywords, Version 1.3.0
The latest versions of this document, the PNG specification, and related
information can always be found at the PNG FTP archive site,
ftp://ftp.simplesystens.org/pub/png/. The maintainers of the PNG
specification can be contacted by e-mail at png-mng-misc @
lists.sourceforge.net.
Abstract
This document is the register of public chunks and keywords in the
Portable Network Graphics (PNG) specification, version 1.2 [PNG-1.2],
and in Portable Network Graphics (PNG) Specification (Second Edition)
[PNG-ISO], plus any additional registered "public" PNG chunks and
keywords, with their date of registration and location of their
specifications.
Some chunks listed here are expected to be less widely supported than
those defined in the basic specification. However, application
authors are encouraged to use these chunk types whenever appropriate
for their applications.
Additional chunk types and keywords may be proposed for inclusion in
these lists by contacting the PNG specification maintainers at
png-mng-misc @ lists.sourceforge.net.
1. Register of Public PNG Chunks
This table lists the registered public PNG chunks.
Chunk Date Formal specification
type registered of chunk type
IDAT 7 Mar 95 PNG 1.2
IEND 7 Mar 95 PNG 1.2
IHDR 7 Mar 95 PNG 1.2
PLTE 7 Mar 95 PNG 1.2
bKGD 7 Mar 95 PNG 1.2
cHRM 7 Mar 95 PNG 1.2
fRAc 7 Mar 95[1] PNGEXT 1.2.0
gAMA 7 Mar 95 PNG 1.2
gIFg 7 Mar 95 PNGEXT 1.2.0
gIFt 7 Mar 95[2] PNGEXT 1.2.0
gIFx 7 Mar 95 PNGEXT 1.2.0
hIST 7 Mar 95 PNG 1.2
iCCP 17 Aug 98 PNG 1.2
iTXt 9 Feb 99 PNG 1.2
oFFs 7 Mar 95 PNGEXT 1.2.0
pCAL 28 Jan 97 PNGEXT 1.2.0
pHYs 7 Mar 95 PNG 1.2
sBIT 7 Mar 95 PNG 1.2
sCAL 7 Mar 95 PNGEXT 1.2.0
sPLT 9 Dec 96 PNG 1.2
sRGB 6 Nov 96 PNG 1.2
sTER 15 Apr 06 PNGEXT 1.3.0
tEXt 7 Mar 95 PNG 1.2
tRNS 7 Mar 95 PNG 1.2
zTXt 7 Mar 95 PNG 1.2
[1] The fRAc chunk was registered but never formally specified.
[2] The gIFT chunk was formally deprecated on 23 Oct 98.
2. Register of Public Text Chunk Keywords
This table lists the keywords that have been registered for use in
PNG textual chunks.
Keyword Date Formal specification
registered of keyword
Title 7 Mar 95 PNG-1.2
Author 7 Mar 95 PNG-1.2
Description 7 Mar 95 PNG-1.2
Copyright 7 Mar 95 PNG-1.2
Creation Time 7 Mar 95 PNG-1.2
Software 7 Mar 95 PNG-1.2
Disclaimer 7 Mar 95 PNG-1.2
Warning 7 Mar 95 PNG-1.2
Source 7 Mar 95 PNG-1.2
Comment 7 Mar 95 PNG-1.2
All registered textual keywords in iTXt and all other chunk types are
limited to the ASCII characters A-Z, a-z, 0-9, space, and the
following 20 symbols:
! " % & ’ ( ) * + , - . / : ; < = > ? _
but not the remaining 12 symbols:
# $ @ [ \ ] ^ ‘ { | } ~
This restricted set is the ISO-646 "invariant" character set
[ISO-646]. These characters have the same numeric codes in all ISO
character sets, including all national variants of ASCII.
3. Appendix: Revision History
* 30 August 2006 (version 1.3.0): Added sTER chunk. Updated some
URLs.
* 21 November 2000 (version 1.2.0): First public release, derived
from the PNG Specification [PNG-1.2] and the PNG Extensions
document [PNGEXT-1.2.0].
4. References
[ISO/IEC-8859-1]
International Organization for Standardization and International
Electrotechnical Commission, "Information Technology--8-bit
Single-Byte Coded Graphic Character Sets--Part 1: Latin Alphabet
No. 1", IS 8859-1, 1998.
Also see sample files at
ftp://ftp.simplesystems.org/pub/png/documents/iso_8859-1.*
[ISO-646]
International Organization for Standardization and International
Electrotechnical Commission, "Information Technology--ISO 7-bit
Coded Character Set for Information Exchange", 1991.
[PNG-1.2]
Randers-Pehrson, G., et. al., "PNG (Portable Network Graphics
Format) Version 1.2", which is available at
ftp://ftp.simplesystems.org/pub/png/documents/.
[PNG-ISO]
"Portable Network Graphics (PNG) Specification (Second Edition),"
10 November 2003, also released as "International Standard
15948:2003 -- Portable Network Graphics (PNG): Functional
specification", available at http://png-
mng.sourceforge.net/pub/png/spec/iso/
[PNGEXT-1.2.0]
Randers-Pehrson, G., et. al., "Extensions to the PNG (Portable
Network Graphics Format) Version 1.2.0", which is available at
ftp://ftp.simplesystems.org/pub/png/documents/.
[PNGEXT-1.3.0]
Randers-Pehrson, G., et. al., "Extensions to the PNG (Portable
Network Graphics Format) Version 1.3.0", which is available at
ftp://ftp.simplesystems.org/pub/png/documents/.
5. Credits
Editor
* Glenn Randers-Pehrson, glennrp @ users.sourceforge.net
Document source
This document was built from the file pngreg-master-20060914 on
14 September 2006.
Copyright Notice
Copyright (c) 2000, 2006 by: Glenn Randers-Pehrson
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register and any associated documentation will at all times remain
with copyright holder.
End of Register of Public PNG Chunks and Keywords 1.3.0