Internet Archaeol. 14. Hopkinson and Winters. Discussion

3. Discussion

Apart from the logistical problem of scanning such large images, the major difficulty encountered during the course of preparing the images was that of accommodating alterations. The ebb and flow of the editorial process meant that each stage was open to comment (and therefore changes) from the author and/or editor; changes such as image scale, captions etc. Layers were employed to separate out different components of a drawing but since each layer was essentially still a raster image, they were sometimes time-consuming and difficult to alter at these later stages. This was particularly true when an image was converted from a monochrome to a colour image, and the resolution changed.

Those figures that were prepared by digitising in CAD software were much easier to manipulate, as they were maintained in a vector format (whether in AutoCAD or Adobe Illustrator) throughout, only being committed to raster format when the final GIF file was exported. With hindsight, all the drawings should have been prepared in this manner since the versatility of a vector drawing easily compensates for the slight increase in time spent digitising 'from scratch' rather than cleaning a scanned image, particularly as a number of the illustrations contain repeated elements. In this respect, it would be interesting to experiment with the use of raster to vector conversion software, such as Adobe Streamline or Able Software's R2V.

While the DWF images form a fairly minor part of the Cricklade article, this publication format holds great potential. The final report actually contains more DWF illustrations than specified in the original brief, due to the fact that some of the plans were digitised rather than cleaned the original scans. This proved a useful method for presenting trench numbers (See DWF images 6a and 6b of the final article - http://intarch.ac.uk/journal/issue14/1/images/fig6.htm) as labelling the trenches on a raster image would have cluttered the entire drawing.

During the preparation of the illustrations for the Cricklade article, the DWF viewer plugin that would be needed to view the files (Autodesk's Whip!) was taken out of service but thankfully this did not cause any major problems since it was superceded by Autodesk's Express Viewer - whose enhancements now include the ability to embed hyperlinks within the DWF (but scheduling meant that this feature was not employed in our files) as well as numerous other display advantages including the ability for users to annotate and add to the image files. But in the future, such features could, for example, mean that a site plan contained a separate layer to illustrate the location from which photographs were taken, with embedded links to those photographs, or links from section lines to the drawn sections. And in theory, therefore, it should be possible to publish the entire visual component of an archive through one drawing.

One drawback of the DWF format is that it requires the Expresss Viewer plug-in in order to view the images, which at the time of writing is currently not available for users of Apple Macintosh computers. Although not quite as versatile as the DWF format, vector based drawings could be published as SVG files, which again require a plug-in but offers greater cross platform access (see Wright 2003). This format was not used in the Cricklade article, but the files could be created by importing a CAD drawing into Adobe Illustrator and then exporting it to the SVG format.