W3C approves new PNG graphics format

By Alun Williams

Posted on 29 May 2003 at 16:10

The World Wide Web Consortium (W3C) - the body responsible for Internet standards - has published PNG Second Edition as a W3C Proposed Recommendation. This is the final stage of approval granted by the standards body.

Now a mature format, PNG (pronounced 'ping') was designed to be a portable and lossless way to transmit compressed graphic images across the Internet. It also enables integrity checking to ensure that what arrives is exactly what was sent and supports the detection of transmission errors

The format is intended to be a patent-free alternative to GIF and, in many cases, TIFF. For example, PNG graphics support the use of true colour in addition to the indexed colour supported by the GIF format. In true colour, RGB values (and an optional alpha channel) are specified whereas indexed colour specifies an entry in a palette. Images that involve subtle degrees of colour change, for example translucency, best show the benefits of true colour.

You can read more W3C information about PNG at www.w3.org/Graphics/PNG/

PNG is also in the final stages of standardisation at ISO (International Standards Organisation), as ISO/IEC 15948.