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The PNG File Format

Last updated: 23 January 2009
Published in: Creating new digital media |
Tags: file formats |

The Portable Network Graphics or PNG format is a versatile file format that is an open standard and provides many advantages.

What is a PNG file?

The Portable Network Graphics or PNG format is a versatile file format that is an open standard and provides many advantages. Among these advantages are 'lossless' compression, full 24-bit colour and transparent layers, which can be read by a web browser. PNG offers many of the advantages of both the TIFF and the GIF file formats whilst providing a smaller compressed file size than either.

If it is so good should I use it for my master archive?

Industry take-up has been slower than many had hoped for this file format but it still provides a useful, reliable and viable alternative to TIFF. Due to its slow take-up and the dominance of TIFF the decision to use PNG as an archival format should be given careful consideration. At present most master archives are stored as uncompressed TIFFs.

Do PNG files offer compression?

Yes. PNG files use an open standard lossless compression. While this will produce smaller files than the equivalent uncompressed TIFFs it does not compare to the compression ratios available in JPEG or JPEG2000.

Has PNG replaced the GIF format?

GIF and PNG both offer transparency but PNG also offers 24-bit colour as opposed to the more limited 8-bit available to GIF images. However, the GIF format is still dominant largely due to the failure of some browsers to fully support PNG transparency.

What about the future?

The future should look bright for the PNG format; widespread browser support for transparency is just around the corner. The PNG format offers advantages over TIFF such as non-proprietary lossless compression. However, formats like JPEG2000 are appearing all the time: this format offers high levels of compression, lossy and lossless, as well as transparency but at present support is minimal.

Last updated: 23 January 2009
Published in: Creating new digital media |
Tags: file formats |

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