Hochschularbeit
| Katharina Lußky: | Lasercleaning of common papers used in the 19th century in combination with typical writing substances. | Zurück |
| Sprache: | Original - Übersetzung | |
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| Zusammenfassung: | This assignment focuses on the cleaning of common papers used in the 19th century in combination with typical writing substances and various types of dirt. For these experiments two common papers of the 19th century were chosen as well as a standard paper used in restauration. These were a Whatman filter paper No.1, a Hadern paper and a wood-based paper. Under controlled conditions three powdery and two liquid writing substances were applied to the papers. The powdery substances were graphite, charcoal and chalk, the liquids were Iron-gall ink and a soot based water-colour. The soiling was simulated with charcoal sticks following the example of earlier experiments where a standard dirt was removed by laser. Due to previous analysis of dirt a standard option by Particle Technology SAE J 726 fine was applied. The original white dirt was blackened with soot to a 20:1 mixture. The chosen application method of the dirt variants was massaging in with a brush, combined with the suction of a vacuum cleaner. By using this combination a very even and uniform soiling could be achieved, which would be easy to reproduce and therefore guaranteed a standardization. Different types of dirt were applied to plain paper as well as papers holding writing substances in the described manner. For the laser cleaning experiments a Nd:YAG laser by IB Laser with a laser parameter of 8ns pulse length, 532nm wave length and a 3 x 3 sqmm prepared area per “Parametersatz” aided by direct focusing. Before the laser treatments the papers and writing substances were examined by microscopical, scanning electron microscopical and colorimetrical analysis methods. The analysis were to support the comparison and assessment o f the laser treated samples. The papers without applications were then lasered to determine the laser induced stages of degradation. Considering energy density for single and multi-plus radiation, the different stages were grouped between 0,4 J/sqcm and 12,8 J/sqcm. After each laser treatment the papers were analyzed microscopically as well as colourimetrically. The stages of treatment for the systems polluted with both dirt variations ranged from 0,01 J/sqcm to 0,07 J/sqcm for single and multi-plus radiation. The required energy for the cleansing process depended on the papers, their surfaces and the different types of dirt. By using the assessments of the stages the working levels of the laser were determined. The Whatman filter paper in conjunction with the Iron-gall ink, soot based water-colour and all types of dirt can be cleaned by using a laser. Both dirt variations can also be removed from the Hadern paper as well as the wood-based paper treated with Iron-gall nut ink. When cleaning papers, on which writing substances have been used, a diversity of parameters have to be considered. Each paper which is to be restored is unique. These tests have shown that the use of lasers in restoration work is very limited at the present time. However, further tests will be necessary, i.e. the paper’s reactions after aging and laser cleaning of aged samples, until it will be possible to use a laser on the originals. |
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| Kontakt: |
Katharina Lußky katelu@[Diesen Teil loeschen]gmx.de |
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