Diplom degree programme thesis abstracts 2009 / publication information

Stefan Lohrengel. Identification and storage of diazotypies oft he Hans-Scharoun-Archive at the Akademie der Künste, Berlin. Diazotypes are commonly found in 20th-century architectural collections such as the Hans-Scharoun-Archiv. It is a direct copying process based on diazonium compounds, where after an exposure under UV-radiation, the non-destroyed compounds react with a coupler, forming an azo dye. Diazotypes on opaque and translucent base papers that exist either with and without a coating or consist of plastic films are identified and described by conducting macroscopical and microscopical visual examinations. In a test series that investigates the sensitivity of diazotypes to alkali, samples are brought in contact with interleafing papers with and without alkaline fillers in a closed system with a fluctuating temperature alternating between 25 and 60 °C. There are hints, that diazotypes are sensitive against alkali. Changes in colour were observed trough visual examinations and spectral photometric measurements. To investigate the sensitivity to oxygen, samples were exposed to a hydrogen peroxide atmosphere. Intense discolorations were identified and this corresponds to the typical damages of the light-induced oxidation of phenols into yellow-brownish compounds. On the basis of the investigation, criteria regarding the folder specifications for conservation storage were established. Diazotypes should not be stored in contact with papers containing an alkaline filler and with little access to oxygen. Publication: S. Lohrengel, Eva Glück. Das Lichtpausverfahren Diazotypie im Hans-Scharoun- Archiv / The photoreproductive process of the diazotype in the Hans Scharoun Archive, in: Eva Glück, Irene Brückle. Eva-Maria Barkhofen. Papier–Linie–Licht. Konservierung von Architekturzeichnungen und Lichtpausen aus dem Hans-Scharoun-Archiv. Akademie der Künste, Berlin, 2012, S. 93–109.

Luise Maul. The manuscript estate of Ernst Jünger. A low-pressure storage concept for minimizing damaging effects of pressure-sensitive tapes present in this collection.The German writer and philosopher Ernst Jünger (1895- 1998) left his literary estate to the German Literature Archive in Marbach. The self-adhesive tapes which Jünger himself used to attach dried plants, insects, feathers and other objects to his manuscripts caused a great deal of damage. Many of the objects are fragile and brittle. The cold flow of acrylate-based adhesive caused many pages to stick together. In order to make the extensive estate accessible to researchers, the German Literature Archive launched a scientific project that aims to investigate the materials, their conservation and their restoration. This thesis focuses on two aspects of the conservation and storage of the estate. Firstly, interleaving materials for separating sticking pages were tested and secondly, a storage system for the damaged part of the estate was developed. Coated polyester films and papers were tested for their suitability as interleaving material, their ability to divide adhered pages and their tendency to develop electrostatic charge after simulated use. The coated interleaving polyester films were artificially aged by exposure to heat and light. After artificial ageing, the stability of the materials was evaluated by means of spectral photometric measurements and by testing their tensile strength. The potential transfer of any coating material from the interleaving to a contacting paper was examined by means of FTIR spectroscopy. In addition, the interleaving materials were also tested for their resistance to abrasion. None of the tested materials could fulfil all of the listed requirements. For application in the estate of Ernst Jünger a siliconized paper with low opacity and thickness is recommended. The development can be realised by the teas SE. Loparex can be accepted as preliminary interleaving material until the new product is available. In order to reduce the continuous load on the objects, a new storage system was designed to replace the old Aurich archive boxes. Cases for the loose and especially vulnerable manuscripts were created for safe storage and use. Manuscripts bound as books or booklets where fitted with paper folders, and a book support was built. This newly developed storage system, including interleaving and featuring mock-up reproductions of the original manuscript pages, was tested on a group of standard users at the Archive and the University. The storage system was optimised on the basis of the results, and guidelines for the use of the Ernst-Jünger estate in the German Literature Archive were formulated. Parts of the estate were transferred to the new storage system as part of this thesis.

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