Formats for preservation
About ten of these systems are still being used. For optimal conservation and control, the videotapes would be ideally stored under continuous conditions; preferred temperature 18ºC (+/- 1ºC) and humidity level 40% RH (+/-5%). Moreover, tapes will wear when they are used, and copies should be used for presentation purposes. Also take care of preventive routine maintenance of all the components of the apparatus, such as guides, pinch rollers, scanners and read/write heads. Not only climatic conditions, but also dust, dirt, ultraviolet radiation, heat and magnetic fields can affect a magnetic tape. For optimal preservation, the information stored on tape should be transferred to another carrier within seven, at the very most ten years. To prevent the tapes from blocking and oxidation, they should be wound and rewound once a year.
Digital Formats in daily use
Digital Betacam for artworks, MPEG2 for documentation, interviews etc. Unique copies and works older then 10 years should get priority in preservation. Preservation of video art entails cleaning of the tapes and migration to another format.
Documentation, consultation with the artists and the conversion of the analogue signal to Digital Betacam have turned out to be the essential criteria for the preservation of video works for the future. Tests and recent developments have shown that Digital Betacam is the best choice for the preservation of these works of art. The signal is compressed in the proportion of 1:2, which is invisible to the human eye. This is in contrast to Mpeg 2, where compression is certainly visible.
Moreover, Digital Betacam is an accepted standard. A higher degree of compression is tolerable for presentation; DVD is more and more often used for this purpose. If the tapes are treated correctly and are stored under the right conditions, works that are preserved in this way can be transferred to a new carrier within ten years, without loss of quality. The status of the material is essential for selection, preservation, and further treatment. Digitisation should be implemented using materials of the highest possible quality. This will have to be as close as possible to the first generation, to the master.
Formats for presentation
MPEG2, MPEG4 & Real Media. The Netherlands Media Art Institute investigated the various formats and systems for digital storage and established procedures. Since then works from the collection have also been distributed on DVD. Works seven years or older are conserved on high quality Digital Betacam's and are digitised from this source. For DVDs and on the internal server MPEG2 is used. For internet presentation of the collection Real Media, in the future MPEG4, for life streaming MPEG4 is used.
The Netherlands Media Art Institute researches several aspects of video streaming: compression, algorithms, broadcasting, encoding technology, licensing, and authentication and archiving. Main requirements are quality of the video play-back, standardisation and longevity. Other parameters are efficiency, costs, compatibility, and integration with adopted technologies.
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