Wall plaster is an excellent medium to encapsulate inscriptions and art graffiti, since the mater... more Wall plaster is an excellent medium to encapsulate inscriptions and art graffiti, since the material is consolidated and relatively resistant to erosion, showing both gypsum and lime plasters were used for writing and engraving artistic features in antiquity. The technological reconstruction of wall plasters that were used for art graffiti and inscriptions could help researchers gain an understanding of their chemistry and preparation processes as a reference for conservation and art studies. To understand if the properties of the base material play a significant role, we characterized
the chemical and structural properties of wall plasters showing incisions of crosses, people with raised hands, and Arabic names, in the Khallat es-Siḥrij reservoir near Rosh ha- ‘Ayin, Israel. In this work we show that three different technologies of plaster were used: lime-earth fine grained material, lime-earth course grained material, and lime-crushed ceramics course grained material. The different silicate minerals that were added to the lime influenced the hydraulicity and therefore the hardness of the plasters. The quality of the writings and engravings of features is comparable,
indicating that a large variability in plaster technology can be used for inscriptions and art graffiti. This suggests cultural preferences and geographic locations could be the main factor in finding graffiti and inscriptions on wall plasters.
Tefillin are Jewish ritual artifacts consisting of leather cases, containing inscribed slips, whi... more Tefillin are Jewish ritual artifacts consisting of leather cases, containing inscribed slips, which are affixed with leather straps to the body of the tefillin practitioner. According to current Jewish ritual law, the tefillin cases and straps are to be colored black. The present study examines seventeen ancient tefillin cases discovered among the Dead Sea Scrolls in caves in the Judean Desert. All seventeen cases display grain surfaces with a very dark, nearly black appearance. We start with a hypothesis that the cases were intentionally colored black in antiquity using either a carbon-based or iron-gall-based paint or dye. The aim of this study is to test this hypothesis by subjecting these tefillin cases to a battery of examinations to assess the presence of carbon and iron used as pigments, and of organic materials which may have been used as binding agents in a paint. The tests deployed are: (1) macroscopic and microscopic analyses; (2) multispectral imaging using infrared wavelengths; (3) Raman spectroscopy; (4) Fourier transform infrared spectroscopy (FTIR); and (5) scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy. The results of these tests found no traces of carbon-based or iron-gall-based pigments, nor of organic compounds which may have served as binders in a paint. These results suggest that our posited hypothesis is unlikely. Instead, results of the SEM examination suggest it more likely that the black color on the surfaces of the tefillin cases is the result of natural degradation of the leather through gelatinization. The Judean Desert tefillin likely represent tefillin practices prior to when the rabbinic prescription on blackening tefillin was widely practiced. Our study suggests that the kind of non-blackened tefillin which the later rabbis rejected in their own times may well have been quite common in earlier times.
Abstract The Dead Sea Scrolls are often described as the most important archaeological find of th... more Abstract The Dead Sea Scrolls are often described as the most important archaeological find of the 20th century. These 2000 years old manuscripts have great religious, historical and linguistic importance. The fact that large parts of these texts are obscured by the darkening of the parchment is extremely unfortunate. In our previous research we explored the possible causes of parchment browning or darkening using artificial aging, which allowed both destructive and non-destructive testing. Our results could be summarized as two main theories, one related to parchment fibers flattening and changing the way light is reflected, the second related to the formation of strong brown pigments, likely from the melanoidin family. Here we examine the scrolls themselves and discuss their degradation in light of these theories. The main DSS collection could only be surveyed by completely non-destructive means, namely multispectral imaging and Diffuse Reflected Infrared Fourier Transform (DRIFT); however, a few fragments were examined by micro-destructive means including SEM and FTIR-ATR and EPR. Despite the great variation between scrolls, we demonstrate that the browning of the scrolls and their degradation fits within the framework of those theories developed on artificially aged samples. We suggest the extreme degradation occurred when parchment was exposed to water and particularly if that water was slow to evaporate, for example saturated salt water which is slow to evaporate, and was very likely present in the caves where the scrolls were found by the Dead Sea. Hydrolysis and denaturation freed the necessary components to meet and initiate the formation of large melanoidins.
Abstract The Dead Sea Scrolls, a two-thousand-year-old parchment corpus of manuscripts, thought t... more Abstract The Dead Sea Scrolls, a two-thousand-year-old parchment corpus of manuscripts, thought to be the most important discovery of the 20th century including the first known copies of the Hebrew Bible, have darkened in parts to the point that the text is illegible. This motivated our research to try to understand the browning of parchment mechanisms. The scrolls cannot be analyzed by any destructive methods, so alternatives had to be sought. Here we describe a series of artificial aging experiments using modern parchment, prepared especially for our project, according to traditional methods, demonstrating how the different types of browning observed on the scrolls relate to environmental conditions as well as post finding treatments. Even the most extreme browning could be caused by prolonged exposure to water. This was in complete variance from controlled relative humidity exposure, where even elevated temperatures over a full five months caused only mild browning. We also confirm browning occurs at room temperature and within short periods when parchment is wet. We noted greater darkening of the flesh side in short term experiments, while browning was similar on both sides in conditions where water or humidity levels were maintained over a longer period. Artificial aging also confirmed the damage to the lower ends of many scrolls was likely caused by capillary actions when parchment was standing in water. That experiment also showed a dark tide-line phenomenon at the wet-dry interface, similar to that observed in paper substrates. Using analytical methods including FTIR, SEM, Light microscopy, UV–Vis and Fluorimetry we found the browning was always associated with denaturation, or loss of structure, mostly due to water and heat. This results in a flattening of the parchment structure which could be altering how light is reflected. However, in one artificial aging experiment the color was clearly seen to migrate and disperse over the parchment, after its initial formation. We believe this means the color is due to dark pigments; therefore, the main mechanism we suggest is melanoidin pigment formation due to a Maillard type reaction between amino acids and sugars or oxidized lipids, which are perhaps freed to react due to denaturation and hydrolysis. The results collected here can serve as an important step towards a full mechanistic understanding of parchment browning.
Journal of Archaeological Science: Reports, Apr 1, 2023
Material studies of ancient plaster can provide invaluable information on pyro-technological adva... more Material studies of ancient plaster can provide invaluable information on pyro-technological advancements, living practices, stylistic preferences and possibly the cultural organization needed to produce the plaster. Past studies have established methods of analysis for calcite and gypsum-based plaster, but studies of dolomiterich plaster can be more complicated. In particular, the useful FTIR-based method for determining the structural organization of calcite, which differentiates pyrogenic and geological calcite, is hindered by the overlapping calcite and dolomite peaks. Therefore, a new FTIR-based calibration is presented for quantifying the dolomite percent of the carbonates. This was tested both on known mixtures and in comparison to XRD analyses of ancient plaster. Weighted mixtures of calcite and dolomite were used to demonstrate the problem that dolomite causes when using FTIR to study calcite’s structural order. Limits were established for when dolomite can be considered a small error versus when additional steps must be taken, such as a density separation step to separate disordered calcite from dolomite-rich samples. These methods were applied to a case study of red-painted plaster floors from PPNB Motza. Two types of plaster were found: the plaster preparation layers which contained large aggregates and, based on the new calibration, a high percent of dolomite and some sediment, while the finishing topcoat was almost pure calcite with finer aggregates. The same technology persisted across the examined PPNB building phases. Additional examination by light microscopy was able to clarify the outlier results and provide possible insight on the use of a sunken floor or basin. These methods can now be applied for comparison studies of plaster across sites and time periods, and could also be useful in geological studies where mixtures of calcite and dolomite are present.
Material studies of ancient plaster can provide invaluable information on pyro-technological adva... more Material studies of ancient plaster can provide invaluable information on pyro-technological advancements, living practices, stylistic preferences and possibly the
cultural organization needed to produce the plaster. Past studies have established methods of analysis for calcite and gypsum-based plaster, but studies of dolomiterich
plaster can be more complicated. In particular, the useful FTIR-based method for determining the structural organization of calcite, which differentiates pyrogenic
and geological calcite, is hindered by the overlapping calcite and dolomite peaks. Therefore, a new FTIR-based calibration is presented for quantifying the
dolomite percent of the carbonates. This was tested both on known mixtures and in comparison to XRD analyses of ancient plaster. Weighted mixtures of calcite and
dolomite were used to demonstrate the problem that dolomite causes when using FTIR to study calcite’s structural order. Limits were established for when dolomite
can be considered a small error versus when additional steps must be taken, such as a density separation step to separate disordered calcite from dolomite-rich
samples. These methods were applied to a case study of red-painted plaster floors from PPNB Motza. Two types of plaster were found: the plaster preparation
layers which contained large aggregates and, based on the new calibration, a high percent of dolomite and some sediment, while the finishing topcoat was almost
pure calcite with finer aggregates. The same technology persisted across the examined PPNB building phases. Additional examination by light microscopy was able to
clarify the outlier results and provide possible insight on the use of a sunken floor or basin. These methods can now be applied for comparison studies of plaster across
sites and time periods, and could also be useful in geological studies where mixtures of calcite and dolomite are present.
CITY OF DAVID - STUDIES OF ANCIENT JERUSALEMT | The 22nd Conference (Hebrew), 2021
A rare bronze oil lamp, shaped like a grotesque face that is cut in half, was discovered buried w... more A rare bronze oil lamp, shaped like a grotesque face that is cut in half, was discovered buried within the foundations of a building dating to the Late Roman Period (late 1st-early 2nd century CE).
This special bronze lamp was deliberately buried in the foundations of the building and, in our opinion, was used as a foundation deposit (a ritual burial of an offering in the foundations of a building). This lamp may have been used as a ritual offering in order to bring good fortune to those inhabiting the building.
The lamp is the only one of its kind found in Jerusalem and just one of a few known to exist in the world. It was made using a mold and follows a common Roman motif similar to a theater mask.
This paper describes the elemental analysis performed as part of an investigation into the cause ... more This paper describes the elemental analysis performed as part of an investigation into the cause of paint delaminating from the ground in some modern paintings. Paintings are very complex systems and there are many variables to consider when determining the cause of any delamination. Composite samples of oil or alkyd paints, over acrylic grounds, were prepared in the lab. Samples were naturally aged for eight years, and some of the samples delaminated. Initial examinations with a hand-held X-ray fluorescence (XRF) unit indicated that zinc could be the common factor in the delaminating samples. The XRF unit has several modes of operation, and corresponding algorithms to interpret the results; however, none of these modes is appropriate for artists ’ materials. The resulting percentages were clearly incorrect. There was not enough material in some of the samples and particularly in the actual paintings examined to allow for destructive testing of all the different paints. More accurat...
This paper describes the elemental analysis performed as part of an investigation into the cause ... more This paper describes the elemental analysis performed as part of an investigation into the cause of paint delaminating from the ground in some modern paintings. Paintings are very complex systems and there are many variables to consider when determining the cause of any delamination. Composite samples of oil or alkyd paints, over acrylic grounds, were prepared in the lab. Samples were naturally aged for eight years, and some of the samples delaminated. Initial examinations with a hand-held X-ray fluorescence (XRF) unit indicated that zinc could be the common factor in the delaminating samples. The XRF unit has several modes of operation, and corresponding algorithms to interpret the results; however, none of these modes is appropriate for artists’ materials. The resulting percentages were clearly incorrect. There was not enough material in some of the samples and particularly in the actual paintings examined to allow for destructive testing of all the different paints. More accurate...
In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for ei... more In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for eight years, some of the samples delaminated. Samples were analyzed with X-ray fluorescence (XRF), inductively coupled plasma (ICP), Fourier transform infrared - attenuated total reflectance (FTIR-ATR) and atomic force microscopy (AFM) as well as other techniques not detailed in this paper. Results indicate the main cause of delamination is metal soaps in the oil paint and particularly zinc soaps. The ground is a minor consideration as well, rougher grounds providing better adhesion than smooth ones.
In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for ei... more In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for eight years, some of the samples delaminated. Samples were analyzed with X-ray fluorescence (XRF), inductively coupled plasma (ICP), Fourier transform infrared - attenuated total reflectance (FTIR-ATR) and atomic force microscopy (AFM) as well as other techniques not detailed in this paper. Results indicate the main cause of delamination is metal soaps in the oil paint and particularly zinc soaps. The ground is a minor consideration as well, rougher grounds providing better adhesion than smooth ones.
Wall plaster is an excellent medium to encapsulate inscriptions and art graffiti, since the mater... more Wall plaster is an excellent medium to encapsulate inscriptions and art graffiti, since the material is consolidated and relatively resistant to erosion, showing both gypsum and lime plasters were used for writing and engraving artistic features in antiquity. The technological reconstruction of wall plasters that were used for art graffiti and inscriptions could help researchers gain an understanding of their chemistry and preparation processes as a reference for conservation and art studies. To understand if the properties of the base material play a significant role, we characterized
the chemical and structural properties of wall plasters showing incisions of crosses, people with raised hands, and Arabic names, in the Khallat es-Siḥrij reservoir near Rosh ha- ‘Ayin, Israel. In this work we show that three different technologies of plaster were used: lime-earth fine grained material, lime-earth course grained material, and lime-crushed ceramics course grained material. The different silicate minerals that were added to the lime influenced the hydraulicity and therefore the hardness of the plasters. The quality of the writings and engravings of features is comparable,
indicating that a large variability in plaster technology can be used for inscriptions and art graffiti. This suggests cultural preferences and geographic locations could be the main factor in finding graffiti and inscriptions on wall plasters.
Tefillin are Jewish ritual artifacts consisting of leather cases, containing inscribed slips, whi... more Tefillin are Jewish ritual artifacts consisting of leather cases, containing inscribed slips, which are affixed with leather straps to the body of the tefillin practitioner. According to current Jewish ritual law, the tefillin cases and straps are to be colored black. The present study examines seventeen ancient tefillin cases discovered among the Dead Sea Scrolls in caves in the Judean Desert. All seventeen cases display grain surfaces with a very dark, nearly black appearance. We start with a hypothesis that the cases were intentionally colored black in antiquity using either a carbon-based or iron-gall-based paint or dye. The aim of this study is to test this hypothesis by subjecting these tefillin cases to a battery of examinations to assess the presence of carbon and iron used as pigments, and of organic materials which may have been used as binding agents in a paint. The tests deployed are: (1) macroscopic and microscopic analyses; (2) multispectral imaging using infrared wavelengths; (3) Raman spectroscopy; (4) Fourier transform infrared spectroscopy (FTIR); and (5) scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy. The results of these tests found no traces of carbon-based or iron-gall-based pigments, nor of organic compounds which may have served as binders in a paint. These results suggest that our posited hypothesis is unlikely. Instead, results of the SEM examination suggest it more likely that the black color on the surfaces of the tefillin cases is the result of natural degradation of the leather through gelatinization. The Judean Desert tefillin likely represent tefillin practices prior to when the rabbinic prescription on blackening tefillin was widely practiced. Our study suggests that the kind of non-blackened tefillin which the later rabbis rejected in their own times may well have been quite common in earlier times.
Abstract The Dead Sea Scrolls are often described as the most important archaeological find of th... more Abstract The Dead Sea Scrolls are often described as the most important archaeological find of the 20th century. These 2000 years old manuscripts have great religious, historical and linguistic importance. The fact that large parts of these texts are obscured by the darkening of the parchment is extremely unfortunate. In our previous research we explored the possible causes of parchment browning or darkening using artificial aging, which allowed both destructive and non-destructive testing. Our results could be summarized as two main theories, one related to parchment fibers flattening and changing the way light is reflected, the second related to the formation of strong brown pigments, likely from the melanoidin family. Here we examine the scrolls themselves and discuss their degradation in light of these theories. The main DSS collection could only be surveyed by completely non-destructive means, namely multispectral imaging and Diffuse Reflected Infrared Fourier Transform (DRIFT); however, a few fragments were examined by micro-destructive means including SEM and FTIR-ATR and EPR. Despite the great variation between scrolls, we demonstrate that the browning of the scrolls and their degradation fits within the framework of those theories developed on artificially aged samples. We suggest the extreme degradation occurred when parchment was exposed to water and particularly if that water was slow to evaporate, for example saturated salt water which is slow to evaporate, and was very likely present in the caves where the scrolls were found by the Dead Sea. Hydrolysis and denaturation freed the necessary components to meet and initiate the formation of large melanoidins.
Abstract The Dead Sea Scrolls, a two-thousand-year-old parchment corpus of manuscripts, thought t... more Abstract The Dead Sea Scrolls, a two-thousand-year-old parchment corpus of manuscripts, thought to be the most important discovery of the 20th century including the first known copies of the Hebrew Bible, have darkened in parts to the point that the text is illegible. This motivated our research to try to understand the browning of parchment mechanisms. The scrolls cannot be analyzed by any destructive methods, so alternatives had to be sought. Here we describe a series of artificial aging experiments using modern parchment, prepared especially for our project, according to traditional methods, demonstrating how the different types of browning observed on the scrolls relate to environmental conditions as well as post finding treatments. Even the most extreme browning could be caused by prolonged exposure to water. This was in complete variance from controlled relative humidity exposure, where even elevated temperatures over a full five months caused only mild browning. We also confirm browning occurs at room temperature and within short periods when parchment is wet. We noted greater darkening of the flesh side in short term experiments, while browning was similar on both sides in conditions where water or humidity levels were maintained over a longer period. Artificial aging also confirmed the damage to the lower ends of many scrolls was likely caused by capillary actions when parchment was standing in water. That experiment also showed a dark tide-line phenomenon at the wet-dry interface, similar to that observed in paper substrates. Using analytical methods including FTIR, SEM, Light microscopy, UV–Vis and Fluorimetry we found the browning was always associated with denaturation, or loss of structure, mostly due to water and heat. This results in a flattening of the parchment structure which could be altering how light is reflected. However, in one artificial aging experiment the color was clearly seen to migrate and disperse over the parchment, after its initial formation. We believe this means the color is due to dark pigments; therefore, the main mechanism we suggest is melanoidin pigment formation due to a Maillard type reaction between amino acids and sugars or oxidized lipids, which are perhaps freed to react due to denaturation and hydrolysis. The results collected here can serve as an important step towards a full mechanistic understanding of parchment browning.
Journal of Archaeological Science: Reports, Apr 1, 2023
Material studies of ancient plaster can provide invaluable information on pyro-technological adva... more Material studies of ancient plaster can provide invaluable information on pyro-technological advancements, living practices, stylistic preferences and possibly the cultural organization needed to produce the plaster. Past studies have established methods of analysis for calcite and gypsum-based plaster, but studies of dolomiterich plaster can be more complicated. In particular, the useful FTIR-based method for determining the structural organization of calcite, which differentiates pyrogenic and geological calcite, is hindered by the overlapping calcite and dolomite peaks. Therefore, a new FTIR-based calibration is presented for quantifying the dolomite percent of the carbonates. This was tested both on known mixtures and in comparison to XRD analyses of ancient plaster. Weighted mixtures of calcite and dolomite were used to demonstrate the problem that dolomite causes when using FTIR to study calcite’s structural order. Limits were established for when dolomite can be considered a small error versus when additional steps must be taken, such as a density separation step to separate disordered calcite from dolomite-rich samples. These methods were applied to a case study of red-painted plaster floors from PPNB Motza. Two types of plaster were found: the plaster preparation layers which contained large aggregates and, based on the new calibration, a high percent of dolomite and some sediment, while the finishing topcoat was almost pure calcite with finer aggregates. The same technology persisted across the examined PPNB building phases. Additional examination by light microscopy was able to clarify the outlier results and provide possible insight on the use of a sunken floor or basin. These methods can now be applied for comparison studies of plaster across sites and time periods, and could also be useful in geological studies where mixtures of calcite and dolomite are present.
Material studies of ancient plaster can provide invaluable information on pyro-technological adva... more Material studies of ancient plaster can provide invaluable information on pyro-technological advancements, living practices, stylistic preferences and possibly the
cultural organization needed to produce the plaster. Past studies have established methods of analysis for calcite and gypsum-based plaster, but studies of dolomiterich
plaster can be more complicated. In particular, the useful FTIR-based method for determining the structural organization of calcite, which differentiates pyrogenic
and geological calcite, is hindered by the overlapping calcite and dolomite peaks. Therefore, a new FTIR-based calibration is presented for quantifying the
dolomite percent of the carbonates. This was tested both on known mixtures and in comparison to XRD analyses of ancient plaster. Weighted mixtures of calcite and
dolomite were used to demonstrate the problem that dolomite causes when using FTIR to study calcite’s structural order. Limits were established for when dolomite
can be considered a small error versus when additional steps must be taken, such as a density separation step to separate disordered calcite from dolomite-rich
samples. These methods were applied to a case study of red-painted plaster floors from PPNB Motza. Two types of plaster were found: the plaster preparation
layers which contained large aggregates and, based on the new calibration, a high percent of dolomite and some sediment, while the finishing topcoat was almost
pure calcite with finer aggregates. The same technology persisted across the examined PPNB building phases. Additional examination by light microscopy was able to
clarify the outlier results and provide possible insight on the use of a sunken floor or basin. These methods can now be applied for comparison studies of plaster across
sites and time periods, and could also be useful in geological studies where mixtures of calcite and dolomite are present.
CITY OF DAVID - STUDIES OF ANCIENT JERUSALEMT | The 22nd Conference (Hebrew), 2021
A rare bronze oil lamp, shaped like a grotesque face that is cut in half, was discovered buried w... more A rare bronze oil lamp, shaped like a grotesque face that is cut in half, was discovered buried within the foundations of a building dating to the Late Roman Period (late 1st-early 2nd century CE).
This special bronze lamp was deliberately buried in the foundations of the building and, in our opinion, was used as a foundation deposit (a ritual burial of an offering in the foundations of a building). This lamp may have been used as a ritual offering in order to bring good fortune to those inhabiting the building.
The lamp is the only one of its kind found in Jerusalem and just one of a few known to exist in the world. It was made using a mold and follows a common Roman motif similar to a theater mask.
This paper describes the elemental analysis performed as part of an investigation into the cause ... more This paper describes the elemental analysis performed as part of an investigation into the cause of paint delaminating from the ground in some modern paintings. Paintings are very complex systems and there are many variables to consider when determining the cause of any delamination. Composite samples of oil or alkyd paints, over acrylic grounds, were prepared in the lab. Samples were naturally aged for eight years, and some of the samples delaminated. Initial examinations with a hand-held X-ray fluorescence (XRF) unit indicated that zinc could be the common factor in the delaminating samples. The XRF unit has several modes of operation, and corresponding algorithms to interpret the results; however, none of these modes is appropriate for artists ’ materials. The resulting percentages were clearly incorrect. There was not enough material in some of the samples and particularly in the actual paintings examined to allow for destructive testing of all the different paints. More accurat...
This paper describes the elemental analysis performed as part of an investigation into the cause ... more This paper describes the elemental analysis performed as part of an investigation into the cause of paint delaminating from the ground in some modern paintings. Paintings are very complex systems and there are many variables to consider when determining the cause of any delamination. Composite samples of oil or alkyd paints, over acrylic grounds, were prepared in the lab. Samples were naturally aged for eight years, and some of the samples delaminated. Initial examinations with a hand-held X-ray fluorescence (XRF) unit indicated that zinc could be the common factor in the delaminating samples. The XRF unit has several modes of operation, and corresponding algorithms to interpret the results; however, none of these modes is appropriate for artists’ materials. The resulting percentages were clearly incorrect. There was not enough material in some of the samples and particularly in the actual paintings examined to allow for destructive testing of all the different paints. More accurate...
In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for ei... more In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for eight years, some of the samples delaminated. Samples were analyzed with X-ray fluorescence (XRF), inductively coupled plasma (ICP), Fourier transform infrared - attenuated total reflectance (FTIR-ATR) and atomic force microscopy (AFM) as well as other techniques not detailed in this paper. Results indicate the main cause of delamination is metal soaps in the oil paint and particularly zinc soaps. The ground is a minor consideration as well, rougher grounds providing better adhesion than smooth ones.
In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for ei... more In a set of composite samples of oil or alkyd paints, over acrylic grounds, naturally aged for eight years, some of the samples delaminated. Samples were analyzed with X-ray fluorescence (XRF), inductively coupled plasma (ICP), Fourier transform infrared - attenuated total reflectance (FTIR-ATR) and atomic force microscopy (AFM) as well as other techniques not detailed in this paper. Results indicate the main cause of delamination is metal soaps in the oil paint and particularly zinc soaps. The ground is a minor consideration as well, rougher grounds providing better adhesion than smooth ones.
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Papers by Yonah Maor
the chemical and structural properties of wall plasters showing incisions of crosses, people with raised hands, and Arabic names, in the Khallat es-Siḥrij reservoir near Rosh ha- ‘Ayin, Israel. In this work we show that three different technologies of plaster were used: lime-earth fine grained material, lime-earth course grained material, and lime-crushed ceramics course grained material. The different silicate minerals that were added to the lime influenced the hydraulicity and therefore the hardness of the plasters. The quality of the writings and engravings of features is comparable,
indicating that a large variability in plaster technology can be used for inscriptions and art graffiti. This suggests cultural preferences and geographic locations could be the main factor in finding graffiti and inscriptions on wall plasters.
cultural organization needed to produce the plaster. Past studies have established methods of analysis for calcite and gypsum-based plaster, but studies of dolomiterich
plaster can be more complicated. In particular, the useful FTIR-based method for determining the structural organization of calcite, which differentiates pyrogenic
and geological calcite, is hindered by the overlapping calcite and dolomite peaks. Therefore, a new FTIR-based calibration is presented for quantifying the
dolomite percent of the carbonates. This was tested both on known mixtures and in comparison to XRD analyses of ancient plaster. Weighted mixtures of calcite and
dolomite were used to demonstrate the problem that dolomite causes when using FTIR to study calcite’s structural order. Limits were established for when dolomite
can be considered a small error versus when additional steps must be taken, such as a density separation step to separate disordered calcite from dolomite-rich
samples. These methods were applied to a case study of red-painted plaster floors from PPNB Motza. Two types of plaster were found: the plaster preparation
layers which contained large aggregates and, based on the new calibration, a high percent of dolomite and some sediment, while the finishing topcoat was almost
pure calcite with finer aggregates. The same technology persisted across the examined PPNB building phases. Additional examination by light microscopy was able to
clarify the outlier results and provide possible insight on the use of a sunken floor or basin. These methods can now be applied for comparison studies of plaster across
sites and time periods, and could also be useful in geological studies where mixtures of calcite and dolomite are present.
This special bronze lamp was deliberately buried in the foundations of the building and, in our opinion, was used as a foundation deposit (a ritual burial of an offering in the foundations of a building). This lamp may have been used as a ritual offering in order to bring good fortune to those inhabiting the building.
The lamp is the only one of its kind found in Jerusalem and just one of a few known to exist in the world. It was made using a mold and follows a common Roman motif similar to a theater mask.
the chemical and structural properties of wall plasters showing incisions of crosses, people with raised hands, and Arabic names, in the Khallat es-Siḥrij reservoir near Rosh ha- ‘Ayin, Israel. In this work we show that three different technologies of plaster were used: lime-earth fine grained material, lime-earth course grained material, and lime-crushed ceramics course grained material. The different silicate minerals that were added to the lime influenced the hydraulicity and therefore the hardness of the plasters. The quality of the writings and engravings of features is comparable,
indicating that a large variability in plaster technology can be used for inscriptions and art graffiti. This suggests cultural preferences and geographic locations could be the main factor in finding graffiti and inscriptions on wall plasters.
cultural organization needed to produce the plaster. Past studies have established methods of analysis for calcite and gypsum-based plaster, but studies of dolomiterich
plaster can be more complicated. In particular, the useful FTIR-based method for determining the structural organization of calcite, which differentiates pyrogenic
and geological calcite, is hindered by the overlapping calcite and dolomite peaks. Therefore, a new FTIR-based calibration is presented for quantifying the
dolomite percent of the carbonates. This was tested both on known mixtures and in comparison to XRD analyses of ancient plaster. Weighted mixtures of calcite and
dolomite were used to demonstrate the problem that dolomite causes when using FTIR to study calcite’s structural order. Limits were established for when dolomite
can be considered a small error versus when additional steps must be taken, such as a density separation step to separate disordered calcite from dolomite-rich
samples. These methods were applied to a case study of red-painted plaster floors from PPNB Motza. Two types of plaster were found: the plaster preparation
layers which contained large aggregates and, based on the new calibration, a high percent of dolomite and some sediment, while the finishing topcoat was almost
pure calcite with finer aggregates. The same technology persisted across the examined PPNB building phases. Additional examination by light microscopy was able to
clarify the outlier results and provide possible insight on the use of a sunken floor or basin. These methods can now be applied for comparison studies of plaster across
sites and time periods, and could also be useful in geological studies where mixtures of calcite and dolomite are present.
This special bronze lamp was deliberately buried in the foundations of the building and, in our opinion, was used as a foundation deposit (a ritual burial of an offering in the foundations of a building). This lamp may have been used as a ritual offering in order to bring good fortune to those inhabiting the building.
The lamp is the only one of its kind found in Jerusalem and just one of a few known to exist in the world. It was made using a mold and follows a common Roman motif similar to a theater mask.