Use of PhotoCD & Portfolio Format in Teaching

Dr Jeff Trahair
Department of Anatomical Sciences

Teaching in the discipline of Anatomy relies on the intensive study of structure as a basis for understanding function. Considerable effort and cost is required to produce the many images which form the mainstay of our teaching. In the past, these images have been produced photographically, which has inherent difficulties.

Firstly, the images are relatively inflexible. Once they are prepared as slides, for example, they cannot be altered or combined with text without considerable effort. This is potentially a costly exercise, should you have several requirements for an image (eg for different courses, to be used in an exam, as part of an image library etc.) and therefore need several different slides. In some respects photo images are entirely inflexible. There is no possibility, for example, of linking images, or instantly enlarging portions of the image should this be useful for teaching purposes.

A second problem is that technical (darkroom) expertise is required to prepare the images properly. The technicians with this expertise usually do not have the discipline knowledge required to produce the images exactly as they are needed, so a labour intensive collaboration can ensue.

With the advent of the digital acquisition of images (from scanners, digital camera, video capture), or digital authoring (from software and image/clip art libraries, or the Internet) many of these limitations can be overcome, providing avenues for creative and constructive input by the author. Image editing software allows the teacher to control all aspects of the image's final appearance, and presentation software can provide links between images or between images and other forms of information, and portions of an image can be enlarged with the press of a button.

However, the matter of cost remains. To be effective, the images need to be full colour and of good quality resolution. Even higher-end desktop PCs can struggle with the task of managing a presentation of 40-60MB, let alone a computer which is portable. As the demands in terms of MB increase, the presentation can slow considerably. In addition, these expensive computers are arguably under utilised, if their resources are relegated to the rather menial task of being used just as slide showing devices. In respect of cost and portability, the old hardware solution, the slide projector, still has the advantage.

How can large libraries of images be efficiently managed, especially for the presentation and creation of student learning modules? How can we have all the advantages offered by computers and the portability of our old and inexpensive slide projectors?

We have been using PhotoCD format and Portfolio as a tool for managing and delivering good quality images. The format stores images in 5 resolutions as an `image pac' of about 6 MB total. (As an indication of the quality, the highest resolution is designed to produce photographic quality poster size prints from dye sublimation colour printers.) The PhotoCD and Portfolio format also allows creation of stand alone presentations and atlases playable on a PhotoCD (or CDi) player (as well as a CDROM). These devices are relatively cheap ($230 - $1000), and the video output can be presented via projection equipment or a TV monitor. Thus, for a simple presentation, it is possible to have rapid access to up to
100-600 (depending on resolution) full colour images using very simple, cheap and reliable (compared to the computer-based options, including web delivery) equipment.

The learning modules on Portfolio are both interactive and flexible. Students and teachers can gather round the television monitor and enlarge portions of an image, or move between images, or images and text, with ease. The modules can be readily accessed outside of class times. Interactivity is developed as part of the authoring process.

The production of PhotoCD material is achieved on the computer. Although PhotoCD can only provide a subset of the computer's capabilities (still images), it does this with a high level of efficiency, and at fraction of the cost. Once the content is finalised, it is transfered to CD using a CD burner.

Yes, we have been using PhotoCD collections in our teaching for 4 years, and have libraries of discs authored by many of the staff in the department. At the very least, a Portfolio presentation or image collection runs just like a slide show (with sound if desired), but in addition supports linking to other images or text. Indexes can be created to add flexibility, so images can be easily redeployed for different teaching demands. The PhotoCD Portfolio thus allows all the advantages of presentation software, but does not slow down with additional demands of large files, or slow delivery over the internet (or intranet). Additional benefits are the stability of the platform and its low cost. The production of high quality image libraries is also an important advantage. If the titles are authored as CDi titles and plyed on suitable hardware, they can incorporate full motion video (MPEG 1) and many other highly sophisticated authoring possibilities.

Five years later…

We certainly could not do without PhotoCDs for our teaching - we are converted to its value. Everyone else seem to prefer solutions that rely on lots of money and expertise, and so resources and equipment that are often not there.