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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:12 |
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Conference: Bucharest University Faculty of Physics 2004 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
Laser cleaning of stone artifacts – synthesis and
comparative testing of various laser regimes of work
Authors:
Adrian Sima
Affiliation:
University of Bucharest, Faculty of Physics - “Optics, Spectroscopy, Plasma, Lasers”
INOE 2000 – CERTO
E-mail
Keywords:
Abstract:
In order to create a friendly instrument in laser cleaning of stone experiments elaboration (for Romanian restorers) it has been created a synthesis of laser parameters (in Romanian language), which are used in major laser application of stone cleaning.
Using the synthesis work, the restorer can make easily a compared study between different types of stone, laser parameters and different collateral effects and permits him to find the optimum combination for a good cleaning process.
In this work is presented the eligibility of laser cleaning method on two types of stone: marble (“roz de Ruºchiþa”) and chalkstone (“calcar de Podeni”). These rock species were chosen mainly because of their different mineralogical composition, physical proprieties and their different resistance to degradation. These stone types are also employed in common buildings, architectural and sculptural artifacts.
In this purpose the experimental samples, were artificially blackened with lampblack for simulating the natural black patinas. The lampblack was applied either on dry surface of the stone, on wet surface and on oiled surface. The experimental laser cleaning was conduced using Nd:YAG laser (Raffaelo – Quanta System) at three different fluencies chosen for these cleaning cases.
Before the samples were treated with lampblack a study of the stone temperature increasing (with time) was made for the same fluencies and for non-destructive regime. In this purpose the temperature values were taken with a thermal camera (ThermaCam E4 – Flir).
After the cleaning work the colorimetric tests and the reflection spectras of the stone surface were made, for comparative purpose, using a spectrophotometer (Jasco V-550, Ubest)
The main purpose of this work is to make a comparative study of these various laser regimes of cleaning work on these two stone types with very different characteristics for obtaining some useful data in the next possible cleaning/restoring work of the stone artifacts.
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