Band 39, Heft 2 -

Traditionally papyrus fragments are stored between glass panels in many museum collections. In most exhibits a white precipitation is formed on the inner surface of the glazing which complicates reading and digitalization. With the help of the present study the question of the origin and possibilities for avoiding these precipitations should be answered. It could be shown that the precipitations consist of the salts sodium chloride and sodium nitrate. The chloride and nitrate ions for the salt formation stem from the papyrus whereas the sodium ions are dissolved from the float glass. By the use of higher-quality glass such as borosilicate glass this process can be prevented or at least slowed down. Furthermore a storage of the exhibits at relative humidities below 0 % is recommended.

Paper documents with severe iron gall ink corrosion are difficult to handle. While a defined treatment for the chemical stabilisation exists already, methods to improve the mechanical stabilisation have yet to be developed. The degradation of the selected objects was so advanced that the documents needed special attention concerning handling and mechanical re-enforcement. After a calciumphytate-calciumhydrogen treatment, documents were lined with light weight Japanese paper and gelatine. A workflow for treating severely degraded iron gall ink documents was developed. Since the removal of objects from the silk screen frames after the wet treatment proved to be too difficult, a PE-board was introduced as an alternative washing support. Most synthetic fleeces such as Hollytex or Paraprint adhere to its granulated surface by mechanical means. This makes PE-board a practical support during any wet treatment of paper-based objects.

The most recent generation of optical disc media available is the Blu-ray format. Blu-rays offer significantly more storage capacity than compact discs (CDs) and digital versatile discs (DVDs) and thus are an attractive option for the storage of large image or audio and video files. However, uncertainty exists on the stability and longevity of Blu-ray discs and the literature does not contain much information on these topics. In this study, the stabilities of Blu-ray formats such as read-only movie discs as well as many different brands of recordable and erasable media were evaluated. Testing involved the exposure of samples to conditions of 80 °C and 85 % relative humidity for intervals up to 84 days. Overall, the stability of the Blu-ray formats was poor with many discs significantly degraded after only 21 days of accelerated ageing. In addition to large increases in error rates, many discs showed easily identifiable visible degradation in several different forms. In a comparison with other optical disc formats examined previously, Blu-ray stability ranked very low. Other data from the study indicated that recording Blu-ray media with low initial error rates is challenging for some brands at this time, which is a factor that ultimately affects longevity.