This report is also available as an Acrobat file.

Contents
Authoring and Design for the WWW

PRINCIPLES AND THEIR IMPLICATIONS

Evaluating interactive information technologies

The evaluation

Functions available

Director offers the fullest range of functions, both in terms of things the end-user can do, and the variety of behaviour which Director can produce in response; HTML and Acrobat (each considered on their own) offer far less. To achieve a seamless integration of media in a fully interactive environment, Director is unrivalled. However, Director does not offer anything very useful to the author or the user who wishes to work with straightforward hypertext. By contrast there are useful built-in hypertext-related functions in HTML browsers like Netscape which are not provided by the other packages. For example, Netscape can use coloured hypertext link marking to indicate to users if a document which is linked to the current one has recently been viewed. This is a genuinely useful facility not found in most other (non-Web) hypertext software. Web browsers can also store and display a history list' showing all the nodes that have been visited in the current session, and keep user-defined lists of topics worth returning to.

These facilities of HTML could be imitated by other packages, but the author would need to do all the work of constructing what is provided gratis in HTML browsers.

Adobe Acrobat allows documents to be presented on the user's screen which strongly resemble the original, even if the fonts of the original document are not present on the user's machine. From the point of view of the graphical appearance of the page it is therefore a strong contender. However its ability to link documents together is crude (Acrobat, p104). And at the time of writing, Acrobat has no integrated multimedia facilities.

As an environment for interesting, expressive design, HTML on its own currently offers little. It has become an important issue to try to design successfully within the limitations of such a system. However, Web pages based only on HTML do offer a set of functions which constitute a good basic hypertext environment. See The future: a better hypertext system? (p52).

Summary conclusions

The issues are essentially these:

Does any of these technologies offer on its own everything that the publisher of interactive electronic material requires? Can any one of the three approaches be omitted, the other two being sufficient for all purposes?
Can these technologies be used effectively together?
If hybrid solutions involving two or three of the available technologies are required, what role should each have?
Are there requirements which even these three technologies used together do not meet?

Does any of these technologies offer everything?

While HTML on its own is effective for offering simple textual and graphic information, the expectations of publishers and end-users are rapidly outstripping anything which it alone can provide. Acrobat offers a poor hypertext system but good control over document appearance, especially where resemblance to actual paper documents is important. It also is the easiest system to use, if used merely to make electronic virtual paper' documents. Director and other interactive multimedia packages are able to offer many facilities which are missing from both HTML and Acrobat.

In Higher Education we will want to make sets of documents which offer possibilities such as these (for instance):

extensive text with effective hypertext linking, and which can be stored at distributed locations
virtual paper' documents
interactive material such as simulations which provide rich forms of interaction and which fully integrate multiple media including sound and animation

For a system of any scale and ambition therefore we must conclude that all three types of technology will be required.

Can these technologies be used together?

It is possible to get the best of all worlds by using HTML as the backbone of Web documents and augmenting it with modules employing other technologies as appropriate. Acrobat documents can be displayed in a separate windows or within the frame structure of a Web page. Shockwave (Director) files can be placed within Web pages or in a frame of their own in frame-based browsers.

Using HTML has meant, until recently, losing out on the strengths of the alternative approaches, principally 1 the full integration of different media, 2 the possibilities of more varied kinds of interaction 3 the visual quality of what can be produced. These problems can begin to be solved by either of two methods:

The plug-in' architecture of popular web browsers means that to an increasing extent we can combine different media on-line as part of Web documents. Some of these media can be fully interactive for example embedding interactive multimedia components made with Director (or similar) into a conventional' Web page. Some additional control over the visual appearance is provided by the development of the HTML standard from version 1 through to version 3. There are also enhancements in proprietary browsers, unfortunately introduced outside the standards process. The most obvious example is the frames facility introduced by Netscape, which allows panes of the browser window to operate independently of one another.
Another solution is to combine Web material with, say, CD-ROM. This idea has attracted considerable commercial interest, since it offers the advantages of the Web (for example for information which changes rapidly) and of other solutions (for example for large movies, sound files or heavily interactive sections). Each part of the package is thus used for what it does best.
Developments to multimedia packages may mean that they themselves can be used effectively for retrieving data from the Web, without the need for a separate browser. (see The future p54)).

In hybrid solutions, what role should each technology have?

It must be emphasised that at present HTML is the only system to provide the structural framework within which other Web technologies can be delivered. Acrobat's weaknesses as a hypertext system rule it out from this role, and Director/Shockwave seems even less likely to be able to fulfil it.

While there is current excitement about putting virtual paper on computer screens, so that something can be printed on paper one day and put on screen the next (whether using Acrobat or some other variant of the same concept) we see this as analogous to regarding the car as a horseless carriage or photography as a form of painting. It fails to acknowledge the different nature of the medium and the possibilities which it offers for rethinking styles of communication, not least in HEIs.

Requirements even these three technologies do not meet?

We have concentrated on three technologies which are paradigmatic of particular approaches. If one listened to the advocates of each system one might think that it alone could provide everything needed. However, it is important to emphasise that for particular purposes other supplemental technologies will be required which are not currently offered even within the three systems described.

Other component facilities which may be needed include drawn (rather than pixel-based) graphics; live video; 3D models; etc. For current information on all such Web technologies, refer to the BrowserWatch site (URL in Web Resources, p110).

For systems of any scale, there will be an increasing reliance on databases at the server end to provide a structured framework for the large quantities of information, comprising many different kinds of media, which will be used and reused for different purposes.

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Graphics Multimedia Virtual Environments Visualisation Contents