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Experimental investigation of environmental and material factors in darkening of historic and modern lead white
No full textThe progressive darkening of lead white represents a critical challenge in the preservation of artworks on paper. The National Gallery of Denmark has witnessed an alarming acceleration of this phenomenon since the early 2000s, with lead white highlights in numerous old master drawings undergoing rapid discolouration. This study investigated the factors contributing to the darkening of lead white, specifically comparing industrially manufactured pigments to historically reproduced ones. The research aimed to determine if modern lead white, typically characterised by a higher proportion of hydrocerussite to cerussite in its composition, is more susceptible to darkening. Lead white paint mock-ups were subjected to hydrogen sulfide exposure under varying environmental (such as temperature and relative humidity levels) and material (such as pigment and binder properties) conditions to examine their impact on pigment stability. Due to the extensive number of variables involved, the investigation focused on a subset of the possible experimental conditions. The results indicated that modern lead white is more prone to rapid darkening, likely due to increased lead hydroxide content and smaller particle size, leading to higher reactivity with hydrogen sulfide. Additionally, the pigment-to-binder ratio significantly influenced darkening, with high ratios exacerbating the issue for both industrially made and historically reproduced pigments. Although temperature and relative humidity had minimal direct effects, elevated temperature and humidity conditions could potentially accelerate deterioration by hastening chemical reactions and promoting hydrogen sulfide dissociation into more reactive ionic species, respectively, thus increasing lead white vulnerability to darkening. However, given the observed greater influence of chemical and structural properties over environmental physical factors in the darkening of lead white, these findings emphasise the crucial role of pollution control and suggest that effective preservation of artworks and historical artefacts containing lead white highlights should prioritise strategies to reduce hydrogen sulfide exposure, rather than solely relying on climate control measures
Kommissionen til Bevaring af danske Forfatteres Manuskripter og Breve:Om et kapitel i det 20. århundredes danske arkiv- og litteraturhistorie
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KNV01577 Bogø Kostskole
Get PDFMuseum Sydøstdanmark udførte en større arkæologisk forundersøgelse forud for etableringen af en sportshal på Bogø Kostskole i Bogø By. Forundersøgelsen afdækkede 381 m2, hvilket svarer til 7,8% af det samlede areal. Der fremkom ingen væsentlig væsentlige fortidsminder, og det noteredes at området var kraftigt præget af en recent forstyrrelse i form af påkørt jord. Arealet blev frigivet til bygherres anlægsarbejde efter endt forundersøgelse
“Saksta” z Lutomierska: Nowe rozważania nad pochodzeniem, funkcją i znaczeniem unikatowej zapinki podkowiastej z wczesnośredniowiecznego cmentarzyska w centralnej Polsce
Get PDFNiniejszy artykuł analizuje kwestie pochodzenia, funkcji oraz znaczenia zapinki podkowiastej znalezionej w grobie ciałopalnym nr 9 na cmentarzysku wczesnośredniowiecznym w Lutomiersku. Ten wykonany ze stopu miedzi zabytek najprawdopodobniej powstał na obszarach bałtyjskich leżących dziś w obrębie Litwy i Łotwy. Jego pojawienie się na ziemiach polskich może być efektem rozmaitych interakcji kulturowych pomiędzy ludnością słowiańską a bałtyjską.This article discusses the matters of origin, function and significance of the penannular brooch found in cremation grave no. 9 in the early medieval cemetery in Lutomersk. This copper alloy find was most likely manufactured in the Baltic areas, which today lie within the borders of Lithuania and Latvia. Its presence in Poland may be the result of various cultural interactions between the Slavic and Baltic peoples
Propaganda balloons get their second wind
No full textIn 2021, a large metal trunk was discovered in the attic of the Danish War Museum in Copenhagen, containing two complete World War Two propaganda balloons, constructed by the British Royal Air Force to drop leaflets over Germany. Because the balloons were designed to self-destruct and often ended up in random locations, very few still exist today. Drones and planes have since replaced balloons, and this discovery provided a unique opportunity to study older communication technology. Optical microscopy revealed that the 350 cm tall and 300 cm wide balloons were sewn from fine cotton coated with vulcanised rubber, similar to that used in raincoats and military uniforms. One balloon was coated in talcum powder, which protects against water, acids, and oxygen. Numerous red spots, cracks, and damage to the textile were due to reactions between moisture, oxygen, and sulfur in the rubber.A preservation strategy has increased knowledge of the propaganda balloons’ significance and availability after 80 years of anonymity in a metal trunk. The balloons were cleaned, leaving only a thin layer of protective talcum, packed flat in transparent, flexible pouches, and sealed to slow down their degradation and preserve them for future generations.<br/
Fishing with Stationary Wooden Structures in Stone Age Denmark: New Evidence from Syltholm Fjord, Southern Lolland
Get PDFAn abundance and diverse range of prehistoric fishing practices was revealed during excavations between 2012 and 2022 at the construction site of the Femern Belt Tunnel, linking the islands of Lolland (Denmark) and Femern (Germany). The waterlogged parts of the prehistoric Syltholm Fjord yielded well preserved organic materials, including the remains of wooden fish traps and weirs, and numerous vertical stakes and posts driven into the former seabed – evidence of long term fishing practices using stationary wooden structures from the Mesolithic to the Bronze Age (c. 4700–900 cal BC). Here, we present the results of a detailed study on these stationary wooden fishing structures, making this the most comprehensive and detailed description of prehistoric passive fishing practices in Syltholm Fjord to date. The exceptional scale of the excavated area (57 ha) and abundance of organic materials encountered during excavations provides us with a rare opportunity to identify individual weir systems and information on their construction, maintenance, and use. To contextualise further, we provide an up-to-date compilation of comparable finds in the Danish archaeological record, including a dataset of directly dated specimens, based on both published and unpublished sources. Our results show that stationary wooden fishing structures are an invaluable archaeological resource, and their study, combining landscape reconstruction, ethnographic analogy, and fishing technology, together with artefactual evidence and radiocarbon dating, allows us to reconstruct prehistoric fishing strategies in depth. Due to the long chronology and diversity of the study materials, our results complement previous research on the many nuances and regional specificities of the persistence of fishing practices in the western Baltic Sea over time, despite introductions of new cultures, populations, and livelihoods. Finally, we emphasise that the Neolithisation process in Northern Europe was not as straightforward and uniform in terms of subsistence as commonly assumed
“Saksta” z Lutomierska: Nowe rozważania nad pochodzeniem, funkcją i znaczeniem unikatowej zapinki podkowiastej z wczesnośredniowiecznego cmentarzyska w centralnej Polsce
Get PDFNiniejszy artykuł analizuje kwestie pochodzenia, funkcji oraz znaczenia zapinki podkowiastej znalezionej w grobie ciałopalnym nr 9 na cmentarzysku wczesnośredniowiecznym w Lutomiersku. Ten wykonany ze stopu miedzi zabytek najprawdopodobniej powstał na obszarach bałtyjskich leżących dziś w obrębie Litwy i Łotwy. Jego pojawienie się na ziemiach polskich może być efektem rozmaitych interakcji kulturowych pomiędzy ludnością słowiańską a bałtyjską.This article discusses the matters of origin, function and significance of the penannular brooch found in cremation grave no. 9 in the early medieval cemetery in Lutomersk. This copper alloy find was most likely manufactured in the Baltic areas, which today lie within the borders of Lithuania and Latvia. Its presence in Poland may be the result of various cultural interactions between the Slavic and Baltic peoples