PNG (Portable Network Graphics) Specification, Tenth Draft
Revision date: 5 May, 1995
This is the tenth draft of the PNG specification.
All future drafts will be backward-compatible with the
graphics file format described by this document.
Implementations are invited, and a reference
implementation is under development; see below.
Archive sites
The latest versions of this document and related information can
always be found at the PNG FTP archive site,
ftp.uu.net:/graphics/png/.
The maintainers of the PNG specification can be contacted by e-mail at
png-info@uunet.uu.net.
At present, this document is available on the World Wide Web from
http://sunsite.unc.edu/boutell/png.html,
but this location may not be as permanent as the ones above.
Changes since draft 9
- Extensive editing
- Clarified interlaced representation of very small images:
no filter bytes are present in an empty pass
- Chunk ordering rules clarified
- Limits set on tEXt chunk keyword length
- cHRM chunk description corrected: CIE x and y, not X and Y
- More extensive explanation of alpha and gamma processing
- Separate document created for extension chunk types
- Permanent archive site and e-mail contact point established
Reference implementation
It is anticipated that a reference implementation
will be available before the end of May 1995.
The reference implementation will be freely usable in all
applications, including commercial applications.
When finished, the reference implementation will be available from
the PNG FTP archive site,
ftp.uu.net:/graphics/png/.
A set of test images will also be prepared and will be available from
the same site.
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