There is a great deal of evidence to suggest that people learn better when visual and sound materials are used in a teaching context. Researchers from a range of disciplines have also suggested that visual materials are of great value either as a core focus or to support the research process. For example, studies looking at the effect of visual materials in education have explored how both short-term and long-term memory is associated with the different hemispheres of the brain, but also which kind of information is best retained through the use of images. The Technical Advisory Service for Images (TASI)  funded by the Joint Information Systems Committee (JISC)  has produced a paper on "The Use of Images to Support Instruction and Presentation"  which pulls much of this research together:
'A number of experiments carried out in the 1970s showed that not only does the brain have an extraordinary capacity to imprint and recall, but that it can do so with no loss of memory. The capacity for recognition memory for pictures is limitless. Pictures have a direct route to long-term memory, each image storing its own information as a coherent 'chunk' or concept (Paivio et al., 1968; Standing et al., 1970; Paivio, 1971; Standing, 1973; Paivio, 1975; Erdelyi and Stein, 1981 and references therein).
'In general, users prefer material which is illustrated (Levie and Lentz, 1982) and regard it as being of higher quality. Levin (1989) states "pictures interact with text to produce levels of comprehension and memory that can exceed what is produced by text alone."'
While these studies are not recent, nevertheless they are still relevant to our digital online environment, an environment which is increasingly rich in non-textual materials. However, finding appropriate visual and sound content that will add real value to our learning, teaching and research in the current landscape still remains a considerable challenge. There are parallel challenges in introducing new users in education to the opportunities offered by digital images and other related materials, and indeed in incentivising them to begin the process of searching for this media in the first place.
In the UK the Higher Education digitisation revolution began in earnest in 1995 when a host of digitisation programmes, online delivery services, and specialised search engines began to emerge. In the area of Images, the eLib  and the Distributed National Electronic Resource (DNER)  Programmes, initiated by JISC, responded to this landscape change by the funding of the Higher Education Library for Images (HELIX)  and later the JISC Image Digitisation Initiative (JIDI)  which digitised image content from 16 collections selected for their scholarly importance. The collections were grouped into subject areas and included Art and Design, Geology and Social history and also parts of special collections, notably the Design Council Archives and the Gertrude Bell Archive. The main aim of JIDI was to create a substantial body of digitised content which, together with other JISC-funded digital image libraries, would form the first step towards building a coherent digital image resource for Higher Education, contributing to JISC's DNER .
The JISC 5/99 Learning and Teaching Programme 2000 - 2003  also digitised a number of image collections held within institutions and contextualised these resources for learning and teaching. Artworld , for example, digitised the collections held at the Sainsbury Centre for the Visual Arts within the University of East Anglia  and collections held at the Oriental Museum at the University of Durham . The Crafts Study Center Project  also digitised the collection of ceramics, textiles, calligraphy, and wood together with reference books, and working notes held at the Crafts Study Centre at the Surrey Institute for Art and Design, University College .
Until comparatively recently there were fewer digitisation initiatives in the area of Moving Pictures and Sound, though of note were Click and Go Video  and Lifesign projects , both funded as part of the JISC 5/99 Learning and Teaching Programme. In 2003 the JISC Digitisation Programme began, creating the NewsFilm Online Project , a partnership between JISC, the British Universities Film and Video Council (BUFVC)  and the ITN which aims to digitise 3,000 hours of news film, totalling 60,000 items of footage from 1896 to date. This will enable users to access digital resources of iconic moments from history and 'repurpose' them within their Virtual Learning and Research Environments. Other projects such as the Spoken Word Project , funded through the Digital Libraries in the Classroom Programme , are collaborating with the BBC to digitise a large amount of material from its sound archive and make this available to teachers in the humanities and other disciplines.
In other parts of the public sector large scale initiatives like the NOF-digitise Programme  have digitised and created collections such as ARCive  which gathers together films, photographs and audio recordings of the world's species into one centralised digital library.
JISC has also made considerable investment recently in the creation and licensing of online delivery of moving picture and sound content through Education Media Online (EMOL)  a collection of moving image and sound, currently freely available to Higher and Further Education institutions throughout the UK. JISC also licences two collections of images that are available to Higher and Further Education through subscription. These are the Education Image Gallery (EIG) , a collection of 50,000 photographic images from the Hulton Getty Collection and Scottish Cultural Resource Access Network (SCRAN) , a collection over 300,000 high-quality copyright-cleared images and 5,000 video-clips and sound files.
Free image collection initiatives fostered by particular communities of interest outside the public sector, such as Stock.Xchng  aimed at designers, have also emerged. Here users can browse through a gallery containing over 100,000 quality stock photos. They can also share their photos with fellow designers and add descriptions and comments and build their own collection or portfolio. For general use there is a site called Flickr  which allows users to do all of the above but also allows them to create RSS newsfeeds for their particular collections. JISC has also fostered community-created images: for example, the Bioscience Image Bank Project , part of the 5/99 Learning and Teaching Programme and co-funded by the Centre for Bioscience of the Higher Education Academy , serves around 4,000 images, many submitted directly by teachers and researchers.
Within the commercial arena, other services such as BlinkxTV  have come to prominence. Running voice recognition software over content from various broadcasting corporations such as CNN and the BBC, these services can be searched by words or phrases, returning to users video streams or podcasts containing mentions of these words or phrases. They also offer other "intelligent" services such as Smart Folders which automatically update the files on users' computers with relevant content without users having to search for it.
As this brief content survey suggests, there is a great deal happening, but this represents only the tip of the iceberg of the new and exciting visual materials that are of potential interest to users within education.
So where do users start their search for digital visual material? Most people's first port of call would be a Google Image search. However, in October 2004 TASI conducted a review of such image search engines and concluded that "for those used to viewing well-indexed collections of quality images, the results of the large automated image search engines will probably disappoint. The poor quality of their offerings is not surprising, since they reflect the randomness and unevenness of the Web... Collection-based image search engines include images selected for quality and indexed by hand. The images they contain are seldom found within the results of general Web search engines. Collection-based engines, then, will usually offer much better results than their search engine counterparts. The commercial and copyright issues will also be much clearer..." 
However, an important caveat is that finding what you are looking for is very much dependent on context and intended use. For example, if you are teaching microbiology and you are looking for a particular image of a cell showing a radial microtubule, Google would probably be effective as much of this kind of research material is available on the Web. However, there is of course no guarantee of visual quality. For example, would it be of high enough resolution to project in a classroom, and moreover is it legal? Many images returned by Google and other search engines are not necessarily accompanied by clear copyright statements. AHDS Visual Arts  (the visual arts centre for the Arts and Humanities Data Service) recently conducted a survey of arts institutions in the UK entitled The Digital Picture: a future for digital images in UK arts education . One of the survey's findings concluded that "...91% think that finding images should be straightforward (unsurprisingly), and in seminar discussions it was clear that many do not believe this to currently be the case.."
JISC's Information Environment Architecture  was developed to help provide a conceptual framework for tackling some of these thorny resource discovery issues. A range of JISC portal projects have also been funded to explore specific aspects of the resource discovery landscape and to develop some pilot portal services. Specifically the JISC Portals Programme  has funded work to tackle the challenges of locating quality images and moving pictures and sound of educational value. The PIXUS Image Portal Project  based at SCRAN, was the first of these JISC initiatives to explore the cross-searching of quality-assured images for the HE and FE sector. It enabled users to cross-search some 700,000 images held in seven separate image collections. The collections that formed part of the image portal demonstrator were from SCRAN, the Arts and Humanities Data Service - Visual Arts, the Wellcome Trust , Bristol BioMed , The Art Museum Image Consortium (AMICO) , Resources for Learning in Scotland (RLS)  and the British Geological Survey (BGS) . In the area of time-based media, a user requirements study for a moving pictures and sound portal  was conducted in November 2003. This highlighted the fact that users were interested in finding relevant resources across multiple formats and that at the same time there was little awareness of which digital collections were available for use by the FE and HE community. The survey concluded that a portal in this area offering easier retrieval of relevant material had the potential greatly to increase the use of time-based media within education.
In September 2005 JISC funded the Visual and Sound Material (VSM)  Portal Scoping Study and Demonstrator Project based at EDINA , initially to conduct a scoping study to explore the functional, software, collection and user needs requirements of a portal to cross-search/harvest still images and time-based media from a single interface. The project will also look at new technology and trends, for example, new standards to allow the embedding of portal services within a variety of user environments. Embedding portal functionality could help to deliver a more seamless experience to users and also allow online portal services provided by JISC and others to be tailored to organisational priorities and goals. For example, tools have been developed to allow standalone portal services to be accessed in an integrated way from within an institutional portal or other Web environment. Standards to support this process have also emerged such as JSR-168 for local embedding within institutions and Web Services for Remote Portals (WSRP) for the use of portal services remotely. Essentially this means that users would not have to go to another website outside their institutional portal, or other preferred environment, to search for appropriate and relevant visual and sound material. The second phase of the project will be to build the portal demonstrator based on the scoping study requirements. This project will conclude in February 2007.
The primary purpose of this work is to stimulate and advance thinking in this area, to develop a firm understanding of user requirements and to use this as a basis for specifying a range of useful portal functions. While much of the exciting new image and moving image and sound content that this article has surveyed remains under-used, there is clearly much to be done to increase the accessibility and prominence of this material in education. Making the hidden more visible is one of the things a portal can certainly do. A visual and sound materials portal clearly has the potential therefore to help us along the way to a point where this media takes the place it truly deserves in the future of our digital educational environment.