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Limitations of spectroscopic methods in the study of earthy pigments
Košařová, V. ; Hradil, David ; Kanický, V.
Nowadays, the spectroscopic methods, above all Infrared Spectroscopy (IR), are the most frequently used analytical methods in the research of cultural heritage, which is mainly caused by easy use and non-invasiveness of these methods and a broad range of their application, which comprises both organic and inorganic substances. Nevertheless, each analytical technique has its detection limits, and the fact that a particular method is suitable for one type of a sample does not automatically mean that it will be appropriate for the identification of another sample. Therefore, the aim of the study is to demonstrate the limitations of both Raman Spectroscopy (RS) and infrared spectroscopy in the study of earthy materials.
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Limity spektroskopických metod při studiu hlinkových pigmentů
Košařová, V. ; Hradil, David ; Kanický, V.
Spektroskopické metody v čele s infračervenou spektroskopií (IČ) jsou dnes nejčastěji používané analytické metody ve výzkumu kulturního dědictví, což je dáno především jejich snadným použitím, nedestruktivitou a šíří aplikace, která zahrnuje organické i anorganické látky.Cílem této studie je proto poukázat na limity aplikací Ramanovy (RS) a infračervené spektroskopie při studiu hlinkových materiálů.
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New kriteria for classification and differentiation between clay and iron oxide pigment sof various origins
Hradil, David ; Hradilová, J. ; Bezdička, Petr
Pigments containing iron, although they form a very large group, have never been considered very suitable for datation of color layers and identification of the origin of the painting, due to their abundant occurrence in nature, good availability and widespread use in all historical and pre-historical periods of time. In this paper we have verified that mineralogical composition of clay minerals in earthy pigments is a suitable tool for more detailed specification of material provenance and, in the case of ground layers, also the provenance of the artwork as such. It was obviously convenient to preferably use raw materials from a close and thus also cheaper source. For the purposes of statistical comparison we evaluated elemental composition of earthy grounds on 70 paintings from the 16(th)-18(th) centuries from Czech collections. We performed detailed mineralogical analyses for a selected representative number of grounds on 35 samples in total. We discerned 6 types of material in total 2 types of boles, 3 types of other earths, and one type representing iron-rich red from oxidized zones of hydrothermal ore deposits. We were able to distinguish between earthy pigments of Central European origin (coming from Czech and Bavarian locations) and those coming from North-Italian sources. Thus we were able to assign anonymous paintings to an appropriate place of origin.
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Pedogeneze území Prahy ovlivněná antropogenní činností
Žigová, Anna ; Šťastný, Martin
Půdní pokryv ovlivněný antropogenní činností se v Praze nachází zejména na území s výskytem spraší. Pro studium pedogeneze byly vybrány lokality s různým typem antropogenního zatížení vzdálené od sebe přibližně 6 km. Půdní profil první charakteristické sekvence byl pohřben pod 2,5 m mocnou vrstvou navážek. V druhé sekvenci byla činností člověka ovlivněna svrchní část půdního profilu. Charakteristika pedogeneze byla provedena na základě zrnitostního složení, hodnot pH, CaCO3, Cox, Nt, kationtové výměnné kapacity a obsahu jílových minerálů. Antropogenní faktor v různé míře ovlivnil charakter pedogenetických procesů. V menší míře byla antropogenní činností ovlivněna pedogeneze v sekvenci s půdním profilem pohřbeným pod vrstvou navážek.
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Soil cover of Přední Kobyla site (Bohemian Karst) genesis: role of clay minerals
Žigová, Anna ; Šťastný, Martin
Soil cover of Přední Kobyla site (Bohemian Karst) is represented by relict soils. Přední Kobyla site is covered by illimerized brown earthifield terra fusca with slight sings of pseudogleization. Fractions 0.01 mm and 0.001 mm from the soil profile are charakterized mainly by kaolinite, illite and quartz. Stage and distribution of plagioclase and feldspar in soil reflect the strong weathering process. In association with clay minerals kaolinite is dominant.
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