This paper presents non-destructive, non-invasive and non-contact techniques of optical and surfa... more This paper presents non-destructive, non-invasive and non-contact techniques of optical and surface metrology applied to surface studies of daguerreotypes. Daguerreotypes, the world's earliest photographs, are positive images developed directly on the surface of silver-clad copper plates. The image is a submicron ultra-fi ne structured surface that exceeds the resolving power of the optical microscope for surface examination and evaluation. White light confocal microscopy is shown to be a useful technique for examining the 3D ultra-fi ne structure of the daguerreotype image. This technique provides quantitative information of surface characteristics using established surface roughness parameters to document the daguerreotype surface. Examination at this level can measure changes due to environmentally induced deterioration, and provide comparative data before and after chemical and physical treatment. Confocal microscopy shows considerable potential in assisting the conservator in evaluating both daguerreotype condition and treatments performed on the fragile image structure.
Recently, we have made tremendous progress in the spectroscopic analysis and laser restoration of... more Recently, we have made tremendous progress in the spectroscopic analysis and laser restoration of tarnished daguerreotypes. Laser induced breakdown spectroscopy (LIBS) has been applied for the first time to both modern and 150-year-old daguerreotypes. In addition to surface and depth profiling, the analysis of colors on "tinted" samples allowed identification of the pigment. These results complement the previous analysis by laser ionization mass spectrometry of the surface composition of clean and tarnished examples of the old photographs. Laser ablation cleaning of the submicrometer tarnish layers has now been clearly demonstrated on numerous daguerreotypes with various extents and types of tarnish. The use of computer controlled XY translation and stable laser beam quality have allowed decisive proof-of-principle examples of laser restoration. The best parameters of laser wavelength, power and pulse duration have been determined. Using digital files of daguerreotype images, straightforward models have been developed that allow for the digital mapping of the surface tarnish. In principle, such maps could guide the computer control of the laser cleaning process.
Laser desorption m ass spectro scopy has been used to characterize both m odern and ; 150-year-ol... more Laser desorption m ass spectro scopy has been used to characterize both m odern and ; 150-year-old daguerreotypes. Such investigations are a necessary prelude to attem pts to clean them of tarnish and other contaminants by laser ablation of the surface layers. Both positive-and negative-ion time-of-¯ight spectra were obtained following YAG laser ablation/desorption at 1064, 532, and 355 nm. Major peaks obtained from several daguerreo types reveal expected elem ents from the substrate (Ag, Cu) as well as the developing (Hg) and gilding (Au) processes. Silver clusters (Ag n) may re¯ect surface desorption of molecules or, alternatively, aggregates form ed in the ejection process. Silver sul® de molecules observed from old daguerreotypes are the signature of the tarnishing process.
Laser ablation mass spectrometry and surface-enhanced Raman spectroscopy have been used to charac... more Laser ablation mass spectrometry and surface-enhanced Raman spectroscopy have been used to characterize both modern and 150 year old daguerreotypes. Such investigations are a necessary prelude to attempts to clean them of tarnish by laser ablation. A demonstration of the successful cleaning of a damaged daguerreotype is presented. .
Laser ablation mass spectrometry and surface-enhanced Raman spectroscopy have been used to charac... more Laser ablation mass spectrometry and surface-enhanced Raman spectroscopy have been used to characterize both modern and 150 year old daguerreotypes. Such investigations are a necessary prelude to attempts to clean them of tarnish by laser ablation. A demonstration of the successful cleaning of a damaged daguerreotype is presented. .
This paper presents non-destructive, non-invasive and non-contact techniques of optical and surfa... more This paper presents non-destructive, non-invasive and non-contact techniques of optical and surface metrology applied to surface studies of daguerreotypes. Daguerreotypes, the world's earliest photographs, are positive images developed directly on the surface of silver-clad copper plates. The image is a submicron ultra-fi ne structured surface that exceeds the resolving power of the optical microscope for surface examination and evaluation. White light confocal microscopy is shown to be a useful technique for examining the 3D ultra-fi ne structure of the daguerreotype image. This technique provides quantitative information of surface characteristics using established surface roughness parameters to document the daguerreotype surface. Examination at this level can measure changes due to environmentally induced deterioration, and provide comparative data before and after chemical and physical treatment. Confocal microscopy shows considerable potential in assisting the conservator in evaluating both daguerreotype condition and treatments performed on the fragile image structure.
Recently, we have made tremendous progress in the spectroscopic analysis and laser restoration of... more Recently, we have made tremendous progress in the spectroscopic analysis and laser restoration of tarnished daguerreotypes. Laser induced breakdown spectroscopy (LIBS) has been applied for the first time to both modern and 150-year-old daguerreotypes. In addition to surface and depth profiling, the analysis of colors on "tinted" samples allowed identification of the pigment. These results complement the previous analysis by laser ionization mass spectrometry of the surface composition of clean and tarnished examples of the old photographs. Laser ablation cleaning of the submicrometer tarnish layers has now been clearly demonstrated on numerous daguerreotypes with various extents and types of tarnish. The use of computer controlled XY translation and stable laser beam quality have allowed decisive proof-of-principle examples of laser restoration. The best parameters of laser wavelength, power and pulse duration have been determined. Using digital files of daguerreotype images, straightforward models have been developed that allow for the digital mapping of the surface tarnish. In principle, such maps could guide the computer control of the laser cleaning process.
Laser desorption m ass spectro scopy has been used to characterize both m odern and ; 150-year-ol... more Laser desorption m ass spectro scopy has been used to characterize both m odern and ; 150-year-old daguerreotypes. Such investigations are a necessary prelude to attem pts to clean them of tarnish and other contaminants by laser ablation of the surface layers. Both positive-and negative-ion time-of-¯ight spectra were obtained following YAG laser ablation/desorption at 1064, 532, and 355 nm. Major peaks obtained from several daguerreo types reveal expected elem ents from the substrate (Ag, Cu) as well as the developing (Hg) and gilding (Au) processes. Silver clusters (Ag n) may re¯ect surface desorption of molecules or, alternatively, aggregates form ed in the ejection process. Silver sul® de molecules observed from old daguerreotypes are the signature of the tarnishing process.
Laser ablation mass spectrometry and surface-enhanced Raman spectroscopy have been used to charac... more Laser ablation mass spectrometry and surface-enhanced Raman spectroscopy have been used to characterize both modern and 150 year old daguerreotypes. Such investigations are a necessary prelude to attempts to clean them of tarnish by laser ablation. A demonstration of the successful cleaning of a damaged daguerreotype is presented. .
Laser ablation mass spectrometry and surface-enhanced Raman spectroscopy have been used to charac... more Laser ablation mass spectrometry and surface-enhanced Raman spectroscopy have been used to characterize both modern and 150 year old daguerreotypes. Such investigations are a necessary prelude to attempts to clean them of tarnish by laser ablation. A demonstration of the successful cleaning of a damaged daguerreotype is presented. .
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Papers by Grant Romer