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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
KNV01027-01 Strandgård II:Sted- og lok.nr. 020503-48, SLKS 18/01475 Matr. nr. 14fz Jersie by, Jersie sogn. Beretning for undersøgelse af palisade anlæg og bebyggelse fra overgangen mellem MN III/IV og MN V samt bebyggelse fra førromersk jernalder periode 2 - 3.
Get PDFDenne beretning omfatter resultaterne af udgravningen af 21.400 m2, undersøgt af Museum Sydøstdanmark forud for byggemodning. Der blev undersøgt dele af et palisadeanlæg fra overgangen mellem MNIII/IV og MN V, fra samme periode er der fundet en del gruber og mindst fire toskibede huse, heraf et med bevaretvægforløb. Derudover blev den vestlige del af en bebyggelse fra førromersk jernalder udgravet. Den østlige del af samme er tidligere undersøgt (KNV00013). Tilsammen har de to undersøgelser afdækket en bebyggelse, der baseret på C14 dateringer er afgrænset til perioden 220 – 80 f.Kr, bestående af tre gårde, der har været stedfaste gennem hovedparten af bebyggelsens levetid samt yderligere et antal gårde, der enten har haft kortere levetid eller er flyttet mere rundt indenfor arealet. Desuden blev der registreret enkelte gruber fra TNB, to mulige toskibede huse der noget uventet er C14 dateret til bronzealder periode 3 – 4, samt bebyggelsesspor i form af enkelte mindre treskibede huse og 4 - stolpeanlæg samt gruber fra bronzealder og ældre førromersk jernalder
Når ting fortæller historien: - Genstande fra udgravningen på Horsegård i Galten
No full textNøj, for en udgravning. En hel have propfuld af stolpehuller, brønde, gruber,huse, stenlægninger og nedgravede dyr. Fra jernalder til nutid, fra møntertil træskosåler, fra potteskår til blyindfattede ruder og så alt det indimellem.Talrige levede liv på samme plet igennem hundredvis af år har sat sine spor.Bogstaveligt talt. Her skal et udvalg af sporene fra Horsegård præsenteres,så de kan fortælle deres egen historie om gårdliv, rygevaner, ejerskifte og omdengang, der var stil over drukspil
