Not Just Decoration: quality graphics for the Web


It is possible to provide high quality graphics on the Web if due consideration is given to the appropriate factors. This need not result in reduced interactive performance if care is taken. Inappropriate choices result in severely sub-optimal graphics which users are quick to see and complain about: bad graphics are very visible. There is increasing demand for high quality graphics. User agents that take note of this trend will have a market advantage.


1. Mosaic for X (the initial platform) is described at

2. Watt, A. and Watt, M. (1992) Advanced Animation and Rendering Techniques. New York : Addison-Wesley. ISBN 0-201-54412-1

3. Glassner, A.S. (1995) Principles of Digital Image Synthesis. San Francisco : Morgan Kaufmann Publishers, Inc. ISBN 1-55860-276-3

4. The GIF 89a specification is widely replicated around the internet. A sample URL is

5. The Tagged Image File Format (TIFF) v.6 specification may be obtained from

6. The Portable Networked Graphics (PNG) specification is at

7. The FIG element of the HTML 3 draft specification is at

8. See for example chapter 7 of Travis, D. (1991) Effective Colour Displays. London : Academic Press. ISBN 0-12-697690-2

9. The design of the Utah Raster Toolkit RLE format is described at

10. Some information about Kodak PhotoCD is at

11. JPEG compression is an International Standard ISO/IEC 10918-1. The FAQ for JPEG is at

12. Wyszecki, G. and Stiles, W.S. (1982) Color Science - Concepts and Methods, Quantitative Data and Formulae. New York : John Wiley & Sons. ISBN 0-471-02106-7

13. The student notes from Lilley, C. Lin, F. Hewitt, W.T.H and Howard, T.L.J.H (1993) Colour in Computer Graphics. Sheffield : CVCP/USDTU. ISBN 1-85889-022-5

14. The Commission Internationale de l'Éclairage web page is at

15. Defined in Colorimetry, 2nd Edition, Publication CIE 15.2-1986. ISBN 3-900-734-00-3

16. Netscape 1.1N for X is described at

17. Arena is described at

18. International Color Consortium Profile v3.0 is at

19. The link model of the HTML 3.0 draft is described at


Thanks to my colleague John Irwin for generating the Rayshade input files used to produce the CIE LUV scatter plots. Thanks also to Tom Lane of the Independent JPEG Group, Dave Martindale, Glenn Randers-Pehrson and others on the PNG mailing list for helpful discussions on the requirements for a quality image format.

About the Author

Chris Lilley []
Computer Graphics Unit, at the University of Manchester
In addition to various aspects of graphical quality, his interests include Web tools for collaborative working, Web standards, and the use of the Web for Education. He is an active participant in the IETF HTML Working Group and a contributor to the PNG working group. He is also the JISC representative to W3C.