Advantages & Disadvantages

All the images of actual architecture for the Split project have been captured from 35mm slides or negatives via a S-VHS camera feeding into a 24-bit frame grabber, and thence to disk, where they are stored in JPEG format in spite of the fact that many of them are monochrome, or grey-scale. Because a 35mm slide has far more definition than can be captured in video resolution, my strategy has been to use a Sony PHV-A7E video camera for copying. The slides (or negatives) are placed in a holder, over constant white light, and the result projected onto a monitor in either VHS or S-VHS format. The machine offers colour balance controls, automatic focussing, white light balancing, and positive/negative modes - and the lens has 6x magnification. With suitable negatives/slides, therefore, three or more video images can be derived from parts of the area of one 35mm original, without much or any loss of resolution.

Note that because these images (whether a whole slide/negative, or just a detail) are presented to the framegrabber as video signals, albeit at S-VHS quality, none of these images can therefore be better than video resolution - but this is, in my opinion, quite sufficient for teaching and basic research purposes.

I have used a scanner only for capturing plans and the prints from the various out-of-copyright architectural manuals I have used, in an attempt to capture sufficient detail to make them readable (although, equally, I might have captured them using a video camera). Scanning positives is time-consuming, and storing the results is disk-consuming. Video resolution seems to me to give the best available balance between quality and efficiency - for both the digitizer and the end-user.

Michael Greenhalgh.

Post Processing

The post processing of the images done by Frans van Hoesel, was done to remove articfacts from the above procedure. Most obvious was a problem with the video camera: many of the images showed a cyan tint in the bright areas; dark areas were always very dark red (which was not much of a problem). In an attempt to make the inlined images more pleasing to the eye, I tried to remove these effects, by eighter turning cyan colored parts into grey colored ones, or turn them into a light yellow color, and thus making those parts look more like limestone.
The images were scaled down to a few standard sizes, and a color reduction step was done. This step is described in a forthcoming article by me.

Frans van hoesel.