Technologies (updated 4 August 2004)

Slide and Negative Scanning

For digitising positive slides, both mounted and unmounted, we have found the Minolta Dimâge Scan Dual II to be quite decent. The software is easy to use and the USB interface is fairly fast on both PCs and Apple Macs. The autofocus and image autocorrection are helpful. The only drawback is speed: scanning in four slides following the suggested protocol of index scan, prescan and then final scan is most time consuming. We would recommend that colleagues invest in a FireWire film scanner, such as the Nikon Super Coolscan 4000 ED, if you have a FireWire-enabled computer and the financial resources to do so. The extra cost is made up for in the time that is saved.

Flatbed Scanning

For digitising photos and images, colour or black and white, we have found the UMAX Astra 6400 FireWire flatbed scanner to be an acceptable and economic purchase. While the software is basic and clumsy, the Adobe Photoshop plugin means that the UMAX custom software can be bypassed and the image is then scanned in directly to your image manipulation application of choice. The speed of the FireWire connection is impressive, and large scans take under a minute rather than the 4-6 minutes common with USB scanners. This is important since a computer is effectively out of action for other tasks when scanning. The weakest part of the scanner is the transparency cover which comes with the Astra 6450 which gives poor results. We recommend using a dedicated film and negative scanner as described above.

Video Tape

Analogue video tape comes in a range of forms and sizes. VHS, VHS-C, Video 8 and Hi 8 are some of the most common. A number of products on the market are designed for digitising analogue video tape (home movies recorded on Hi 8 Camcorders or feature films recorded onto VHS directly from television). We would advise against these devices since they provide a costly (and often clumsy) way of resolving a simple problem. Most high-end or 'prosumer' digital camcorders have an inbuilt DV-In socket as well as the standard DV-Out. DV-In enabled camcorders, such as the wonderful SONY DCR TRV 900 and its replacement, the SONY DCR TRV 950, can also digitise older analogue video tape. The older player or camera should then be connected to the DV-In digital camcorder using a high quality S-Video cable for visual information and a pair of audio plugs (white and red). The result is a digitised copy of the original, which can then be captured by a computer using a FireWire connection and edited as with any other digital video material. The only risk here is that this spooling back and forth wears down the heads of the camera. If you have the resources to do so, invest in a SONY GV-D900 video walkman.

8mm and 16mm film

The high costs associated with the digitisation of 8mm and 16mm film, such as investing in a telecine machine, have resulted in the Digital Himalaya team exploring cheaper avenues of film digitisation. Building on the experience of Cambridge staff and technicians, and through the expert advice of the Manager of the Cambridge University Moving Image Studio (CUMIS), we acquired and assembled a SONY Color Film Chain Adaptor, and ingenious device containing a sequence of mirrors which facilitates digitisation of 8mm and 16mm film. The film is projected through the Film Chain Adaptor, recorded with a 3-chip SONY digital camcorder onto 3-hour DVCam tapes using a DVCam recording deck (such as the DHR1000UX). The image below illustrates the system.




We have found the Film Chain Adaptor to be very good when digitising film, and the difference in quality between this system and professional telecine projection is not sufficient to warrant the great differential in cost.

Video Data Compression

In order to watch moving images over the web, streaming or otherwise, the movie file in question must be compressed. Data compression for videos is a complex topic and we refer interested readers to an excellent page devoted solely to this topic which is maintained by our partners in Virginia, the Tibetan and Himalayan Digital Library (THDL). At Digital Himalaya, we have opted for QuickTime as our preferred delivery medium and multimedia architecture, and have chosen to encode most of the video clips in MPEG 4.