What about Phenol Formaldehyde (PF) Foam in Modern-Contemporary Art? Insights into the Unaged and Naturally Aged Material by a Multi-Analytical Approach

The ageing behavior of phenol formaldehyde (PF) foam, a material increasingly used in modern‐contemporary art, was investigated by a multi‐analytical approach. PF foams with open and closed‐cell structures were selected and analyzed in their unaged and naturally indoor‐aged state by employing optical microscopy (OM) and fiber optical reflectance spectroscopy (FORS) for assessing their morphology and color alteration. Micro‐Fourier transform infrared spectroscopy (μ‐ FTIR) was used for determining chemical changes and oxidation processes, and the acidity was monitored by pH measurements. The results clearly showed the extreme sensitivity of both open and closed‐cell PF foams to conditions typically found in indoor museums. OM indicated that the cells of the foams are prone to disrupt, and a tendency towards a red color shift was observed with FORS. μ‐FTIR revealed the formation of quinone groups resulting from oxidation reactions. Finally, a slight decrease in the acidity was found by pH measurements.The ageing behavior of phenol formaldehyde (PF) foam, a material increasingly used in modern‐contemporary art, was investigated by a multi‐analytical approach. PF foams with open-and closed‐cell structures were selected and analyzed in their unaged and naturally indoor‐aged state by employing optical microscopy (OM) and fiber optical reflectance spectroscopy (FORS) for assessing their morphology and color alteration. Micro‐Fourier transform infrared spectroscopy (μ‐ FTIR) was used for determining chemical changes and oxidation processes, and the acidity was monitored by pH measurements. The results clearly showed the extreme sensitivity of both open-and closed‐cell PF foams to conditions typically found in indoor museums. OM indicated that the cells of the foams are prone to disrupt, and a tendency towards a red color shift was observed with FORS. μ‐FTIR revealed the formation of quinone groups resulting from oxidation reactions. Finally, a slight decrease in the acidity was found by pH measurements

Printing sub-micron structures using Talbot mask-aligner lithography with a 193 nm CW laser light source

A continuous improvement of resolution in mask-aligner lithography is sought after to meet the requirements of an ever decreasing minimum feature size in back-end processes. For periodic structures, utilizing the Talbot effect for lithography has emerged as a viable path. Here, by combining the Talbot effect with a continuous wave laser source emitting at 193 nm, we demonstrate successfully the fabrication of periodic arrays in silicon substrates with sub-micron feature sizes. The excellent coherence and the superior brilliance of this light source, compared to more traditional mercury lamps and excimer lasers as light source, enables the efficient beam shaping and a reduced minimum feature size at a fixed gap of 20 μm. We present a comprehensive study of proximity printing with this system, including simulations and selected experimental results of prints in up to the fourth Talbot plane. This printing technology can be used to manufacture optical metasurfaces, bio-sensor arrays, membranes, or microchannel plates

Printing sub-micron structures using Talbot mask-aligner lithography with a 193 nm CW laser light source

A continuous improvement of resolution in mask-aligner lithography is sought after to meet the requirements of an ever decreasing minimum feature size in back-end processes. For periodic structures, utilizing the Talbot effect for lithography has emerged as a viable path. Here, by combining the Talbot effect with a continuous wave laser source emitting at 193 nm, we demonstrate successfully the fabrication of periodic arrays in silicon substrates with sub-micron feature sizes. The excellent coherence and the superior brilliance of this light source, compared to more traditional mercury lamps and excimer lasers as light source, enables the efficient beam shaping and a reduced minimum feature size at a fixed gap of 20 µm. We present a comprehensive study of proximity printing with this system, including simulations and selected experimental results of prints in up to the fourth Talbot plane. This printing technology can be used to manufacture optical metasurfaces, bio-sensor arrays, membranes, or microchannel plates

Enabling proximity mask-aligner lithography with a 193nm CW light source

We introduce a novel industrial grade 193nm continuous-wave laser light source for proximity mask-aligner lithography. A diode seed laser in master-oscillator power-amplification configuraton is frequency-quadrupled using lithiumtriborate and potassium-fluoro-beryllo-borate non-linear crystals. The large coherence-length of this monomodal laser is controlled by static and rotating shaped random diffusers. Beam shaping with imaging and non-imaging homogenizers realized with diffractive and refractive micro-optical elements is compared in simulation and measurement. We demonstrate resolution patterns offering resolutions <2 µm printed with proximity gaps of 20 µm

Mask-aligner Talbot lithography using a 193 nm CW light source

We present and discuss Talbot mask-aligner lithography, relying on a continuous wave laser emitting at 193nm for the illumination. In this source, a diode laser at 772nm is amplified by a tapered amplifier in master-oscillator power-amplifier configuration and frequency-quadrupled in two subsequent enhancement cavities using lithium triborate and potassium fluoro-beryllo-borate nonlinear crystals to generate the emission at 193 nm. The high coherence and brilliance of such an illumination source is predestined for plane wave mask-aligner illumination, crucial in particular for high-resolution lithographic techniques such as Talbot lithography and phase-shift masks. Talbot lithography takes advantage of the diffraction effect to image periodic mask features via self-replication in multiples of the Talbot distance behind the photomask when exposed by a plane wave. By placing a photoresistcoated wafer in one of the Talbot planes, the mask pattern is replicated in the resist. Periodic patterns with diverse shapes are required for wire grid polarizers, diffraction gratings, and hole arrays in photonic applications as well as for filters and membranes. Using an amplitude mask with periodic structures, we demonstrate here with such a technique sub-micron feature sizes for various designs at a proximity gap of 20 µm

Semiconductor-based narrow-line and high-brilliance 193-nm laser system for industrial applications

We present a novel industrial-grade prototype version of a continuous-wave 193 nm laser system entirely based on solid state pump laser technology. Deep-ultraviolet emission is realized by frequency-quadrupling an amplified diode laser and up to 20 mW of optical power were generated using the nonlinear crystal KBBF. We demonstrate the lifetime of the laser system for different output power levels and environmental conditions. The high stability of our setup was proven in > 500 h measurements on a single spot, a crystal shifter multiplies the lifetime to match industrial requirements. This laser improves the relative intensity noise, brilliance, wall-plug efficiency and maintenance cost significantly. We discuss first lithographic experiments making use of this improvement in photon efficiency

Characterization of Pigment-Binding Media Systems in Art by FTIR and UV/Vis/NIR Spoectroscopy

Zusammenfassung in englischer SpracheAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersIm Mittelpunkt dieser Dissertationsarbeit steht die Anwendung der im Reflexionsmodus zerstörungsfrei einsetzbaren verbindungsspezifischen Methoden der UV/Vis/NIR- (ultraviolette, sichtbare und nahe Infrarot Strahlung) und FTIR- (Fourier Transform Infrared) Spektroskopie. Ausgehend von kommerziell erhältlichen Messinstrumenten wurden Messsysteme entwickelt und gebaut, die speziell für die Untersuchung von Kunstobjekten eingesetzt werden können. Diese Messsysteme wurden zur Materialanalyse bei verschiedenartigen Kunstobjekten (Aquarellbildern, Ölgemälden und graphischen Objekten) verwendet. Da die Identifizierung der dafür verwendeten Materialien bei beiden Methoden durch Vergleich mit Referenzmaterialien erfolgt, ist die Aufarbeitung geeigneter Referenzsubstanzen und Erstellung adäquater Datenbanken mit Referenzspektren ein weiterer Schwerpunkt dieser Arbeit. So werden hier zwei neu entwickelte Prozeduren vorgestellt, mit denen unter Verwendung originaler Malmaterialien aus dem 19. Jahrhundert bei minimalem Probenbedarf sehr aussagekräftige Spektrendatenbanken erstellt werden konnten. Die Ergebnisse der Untersuchungen zeigten, dass der Einsatz der UV/Vis/NIR- und FTIR-Spektroskopie im Reflexionsmodus die zerstörungsfreie Identifizierung einer Vielzahl sowohl organischer als auch anorganischer Materialien ermöglicht und insbesondere in Kombination mit der elementspezifischen Röntgenfluoreszenzanalyse (RFA) weitreichende materialtechnische Informationen über Kunstobjekte gewonnen werden können. Es zeigte sich weiters, dass ein Vergleich der Ergebnisse dieser komplementären Techniken die Interpretation der erhaltenen Spektren bei den jeweiligen Methoden erleichtert und sehr zuverlässige Resultate erzielt werden können. Wie zu erwarten zeigte sich aber auch, dass aufgrund prinzipieller methodischer Limitationen eine Reihe häufig verwendeter Pigmente, insbesondere Schwarz auf Kohlenstoffbasis, Erdpigmente und Farblacke nicht zuverlässig identifiziert werden konnten und dass dafür zusätzliche Methoden wie Raman- Spektroskopie oder Röntgendiffraktion (XRD) nötig wären. Ebenfalls methodisch bedingt konnten nur wenige Informationen über die Verteilung der Pigmente in übereinanderliegenden Malschichten gewonnen werden, weshalb dafür wohl auch zumindest in näherer Zukunft nicht auf Probenahme verzichtet werden kann, um eine umfassende technologische Charakterisierung von Kunstwerken zu ermöglichen.The main focus of this doctoral thesis is on the non-destructive analysis of art objects by using compound specific reflection-UV/Vis/NIR and reflection-FTIR spectroscopy. Based on commercially available instruments, measuring systems have been designed and built to meet the specific requirements of material analysis in the field of art. These systems have been utilized to analyse different types of art objects (watercolour paintings, easel paintings, contemporary graphic art objects) in order to identify the materials used by the artists. Furthermore, two new procedures are presented which allow to build up adequate reference databases from only minimal sample amounts of original watercolour materials of the 19th century. This is a crucial point as both methods require references for the identification of the materials. The results obtained demonstrate that UV/Vis/NIR and FTIR spectroscopy in reflection mode enable the non-destructive identification of a variety of both, organic and inorganic materials, particularly in combination with element specific XRF (X-ray fluorescence analysis) and thus are valuable tools for the analysis of cultural heritage objects. Furthermore, the results have shown that a comparison of the complementary methods strongly facilitated the evaluation of spectra obtained by the particular analytical techniques and hence reliable results could be obtained in many cases. As expected, several frequently used pigments e.g. carbon based blacks, earth pigments and lake pigments could not be identified unambiguously due to methodical limitations. Therefore, the use of additional complementary methods such as Raman spectroscopy and X-ray diffraction (XRD) would be highly desirable. Except a few examples, the characteristics of the radiation used for the investigations did not allow to draw conclusions about the distribution of materials in multilayer structures. For this reason, it still remains necessary to analyse cross-sections of samples for a comprehensive technological characterization of art objects, at least in the near future.27

Azurite in medieval illuminated manuscripts: a reflection-FTIR study concerning the characterization of binding media

Abstract In illuminated manuscripts, a reliable identification of oxyanion pigments such as azurite by rFTIR is simple, as several combination and overtone bands are strongly enhanced compared to transmission mode. However, the characterization of the used binding media is rather difficult, as the analysis of four medieval manuscripts from the late thirteenth to the fifteenth century (e.g. Cod. slav. 8 in the collection of the Austrian National Library), as well as the earliest known map of Vienna (Albertinischer Plan from 1421, Wien Museum) showed. According to the literature, mainly glair (egg white) and plant gums were applied as binding media for azurite. Moreover, both were used in many cases also as “varnishes” in order to improve optical and mechanical properties of the paint layer. In order to assess the possibilities and to distinguish between proteinaceous and carbohydrate binders, mock-ups with azurite were prepared on parchment support with various quantities of binders. Additionally, some of the specimen were varnished using the binders mentioned above. Furthermore, mock-ups on aluminium foil were prepared to evaluate the influence of the support on the reflection spectra. The results showed that the binding medium content in the mock-ups usually was too low for a reliable determination by rFTIR (except the ones with the highest contents), whereas it was possible to characterize the varnish materials. Only an insignificant influence of the support on the spectra from the mock-ups was observed. However, the spectra obtained from three manuscripts suggested a certain influence of the parchment support, which indicates thinner paint layers

Multianalytical approach for the analysis of the Codices Millenarius Maior and Millenarius Minor in Kremsmuenster Abbey, Upper Austria

Abstract Two precious Carolingian manuscripts kept in the library of Kremsmuenster Abbey in Upper Austria were subject of investigation. The well-known Codices Millenarius Maior (Inv. No. CC Cim 1, Fig. 1a) and Millenarius Minor (Inv. No. CC Cim 2, Fig. 1b) were studied within the framework of the Centre of Image and Material Analysis in Cultural Heritage (CIMA) in Vienna. The manuscripts are especially famous for their precious and colorful miniatures of a very early medieval period. The aim of the work was the material identification (colors and inks) used for the make-up of the two codices in order to gain a better understanding of their evolution and their provenance. The instrumentation available in the CIMA laboratories allowed performing in situ measurements using non-destructive and non-invasive analytical methods. The investigations comprised a combination of three complementary methods: X-ray fluorescence analysis (XRF), Fourier transform infrared spectrometry in the reflection mode (rFTIR) and Raman spectrometry. In addition to the identification of the pigments and inks also a detailed characterization of the parchment concerning its manufacturing process was achieved by that combination. The identification of calcium carbonates on the surface of the parchment is an indicator for the liming or whitening of the animal skin, whereas the polishing process of the parchment surface with pumice stone, left traces of silicates, detected by rFTIR. The combination of XRF and Raman spectrometry enabled the characterization of black/brown inks in the text revealing the usage of iron gall inks. For the red inks applied for text and initials vermilion and red lead were applied in both codices. Furthermore, the pigment palette used for the illumination included: lead white, orpiment/realgar, red lead, vermilion and red iron oxides as well as azurite and indigo, together with the rather rare copper chloride hydroxide. Furthermore, in both gospels the application of metal leaves as well as powders made of silver–copper and gold–copper alloys could be determined by XRF on several folios