By Sandra Santos

1. CLEANING ART OBJECTS BY
LASER
Sandra Santos
English Class
OPTOELECTRÓNICA CML-DMC-DPC-DPC

2. TOPICS
Laser cleaning
Why laser? Some artwork aplications
How do lasers work?
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3. STANDARD SYSTEMS
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4. STANDARD SYSTEMS
Source: “ARTWORK CONSERVATION BY LASER”
http://alpha1.infim.ro/cost/
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5. STANDARD SYSTEMS
d)
a)
Fig. 1: Lynton Laser
c)
Nd:YAG - L1
a) articulated arm;
b)
b) worktable;
c) exhausting
e) system;
d) laser control
panel;
e) command and
safety labels.
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6. HOW DO LASERS WORK?
Reflecting
surface
Basic Process: selective vaporization of black crusts
(Source : “Laser Cleaning in Conservation”, Martin Cooper)
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7. EXPERIMENTAL CLEANING OF METALLIC MATERIALS
Description: Around the drum-shaped pedestal
surmounting the granite basement, four shacked
prisoners in posestheanguish resignation are seated
Monument to of Memory of the late
on Lord Nelson – de 1813, Liverpool
blocks positioned at the cardinal points: they
represent Nelson’s fourstone and bronze,Cape St.
Sculpture group in great victories at
located in Exchange Flags Square,
Vincent, the Nile, Copenhagen, and Trafalgar.
Between the designed set Matthew drum are four
Liverpool, prisoners by into the Cotes
Wyatt and scalped by Sir Richard
bronze bas-reliefs depicting various naval actions in
which Nelson engaged. Encircling granite bellow
Westmacott, composed by a the drum
basement and a marble Westmorland.
the cornice are swags of laurel, four longer ones
above sculptural work in made shorter above the
The the relieves and four in bronze.
prisoners. The swags are slung 4,3 m.
Height of bronze group: from behind lion’s
heads located at the2,1 m corners of the pilasters
Figures top each.
framing the prisoners. Surmounting all is the
Apotheosis group.
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8. EXPERIMENTAL CLEANING OF METALLIC MATERIALS
Prisoners
Corrosion. Rust. Soiling. Concretions.
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9. EXPERIMENTAL CLEANING OF METALLIC MATERIALS
Prisoners
Before the leg cleaning
During the cleaning work
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10. EXPERIMENTAL CLEANING OF METALLIC MATERIALS
Prisoners
Fluence
SPOT Energy
Distance Diameter Area Aplied
(mm) (mm) (cm2) E/P (mJ) (J/cm2)
120 5,2 0,21 358-371 1,7
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11. EXPERIMENTAL CLEANING OF METALLIC MATERIALS
Letters belonging to the inscription
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12. ANALYSIS OF RESULTS TO THE MICROSCOPE
Over cleaned surface
Damaged surface
Laser
cleaning
Before irradiation E/P = 125mJ
Corroded surface Fi = 10 Hz
salts accumulation F= 0,6 J/cm2
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13. EXPERIMENTAL CLEANING OF METALLIC MATERIALS
Microphotograph of brass surface
before the irradiation. Image with
Magnification 16 x. Width of
original image 21 cm.
Laser
cleaning
Before irradiation E/P = 81 mJ
Corroded surface Fi = 10 Hz
salts accumulation F= 0,2 J/cm2
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14. ANALYSIS OF RESULTS TO THE MICROSCOPE
Corrosion removal whithout causing damage on the
surface - acceptable cleaning level
E/P = 154 mJ, Fi = 10 Hz E/P = 125mJ, Fi = 10 Hz
F= 0,4 J/cm2 F = 0,3J/cm2, wet surface
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15. FINAL RESULTS
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16. FINAL RESULTS
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17. OPTOELECTRÓNICA CML-DMC-DPC-DPC