Stained wood The identification of natural dyes and mordants in wooden works of art
Achim Unger and Wibke Unger
IRG 41st Annual Meeting, Biarritz, France, 09 -13 May 2010 Dyestuffs from the nature and industry
Natural dyes Synthetic dyes
Dyes from Coal tar dyes plants Aniline dyes Azo dyes animals Anthraquinone dyes fungi Sulfur dyes Nitro and nitroso dyes
Rasped natural - colored Historic packaging for wood and roots methyl violet Dyestuffs of vegetable origin
Wood Old fustic, Brazil wood
Bark Black oak
Fruits Common buckthorn
Leaves Indigo plant
Roots Madder, Turmeric
Flowers Safflower
Seed Annatto
Lichen Orchella weed Dyestuffs of animal origin
Insects Marine snails Cuttle fish
Kermes, Lac-insect, Tyrian Purple Sepia Cochineal
Peter-Paul Rubens The dog of the Phoenician god Melqart discovers the spiny dye- murex Dyestuffs of fungal origin
„Mycodyes“ Pynoporus cinnabarinus Cinnabarin
Chlorociboria sp. Xylindein
Phanerochaete sanguinea Xylerythrines
Pulcherricium caeruleum Terphenols Classification of natural dyes based on the dyeing method
Natural dyes
Mordant dyes Direct dyes Vat dyes
Pre-treatment of fiber Dyeing of fiber Soaking of fiber mate- material with metal material without rial into a solution of the salts pre-treatment reduced dye. After removal from the vat oxidation to the real dye on the material
Examples Examples Examples
Alizarin Berberine Indigo Brazilin Carthamin Tyrian Carminic acid Curcumin Purple Analytical procedures for identification of dyes and mordants
Methods
Dyes Mordants
Non-destructive
UV/Vis spectrometry (UV/Vis) X-ray fluorescence 3D fluorescence spectrometry spectrometry (XRF)
Destructive
High-performance liquid Atomic emission spectrometry chromatography (HPLC) (AES)
Thin layer chromatography (TLC) Red-stained wood (I) Application of extracts from Brazil wood
Brazil wood (Caesalpinia sp.) Shutter cabinet, David Roentgen, 1773
Brazilin –absorption spectrum and formula Parquet flooring, Spindler Brothers, 1765 Red-stained wood (II) Application of extracts from Cochineal
American Cochineal (Dactylopius coccus) on the nopal cactus Toilet table, Abraham Roentgen, 1765
Rose intarsia stained with Carminic acid – cochineal extract absorption spectrum and formula Yellow-stained wood (I) Application of extracts from European barberry
European barberry (Berberis vulgaris) Augsburg cabinet, 1560/70
Barberry wood Maple intarsia yellow-stained with an extract from barberry wood Berberine –absorption spectrum and formula Yellow-stained wood (II) Application of extracts from Turmeric
Turmeric (Curcuma longa) „The Holy Rochus“, Wood paneling, Spindler marquetry painting, Brothers, 1765-68 Spindler Brothers, 1770
Reverse side of curcuma- stained intarsia Curcumin –absorption spectrum and formula Blue-stained wood (I) Application of Indigo (I)
Woad (Isatis tinctoria) Preliminary stage: Isatan B Distribution map of indigo species
Indigo plant (Indigofera tinctoria) Preliminary stage: Indican Blue-stained wood (II) Application of Indigo (II)
Woad Indigo plant
Leaves dried on
Woad mill in Thuringia, Germany, 1910
Indigo dye balls Woad ball Blue-stained wood (III) Application of Indigo (III)
Indican or Isatan B
Fermentation
Indoxyl (+ Glucose)
Air
Indigo
Indigo Leuco - Indigo Blue-stained wood (IV) Application of Indigo (IV)
Tyrolese cabinet , around 1630, Grassi-Museum Leipzig, Germany
Shavings stained with indigo Blue-stained wood (V) Application of Indigodisulfonic acid (Indigo carmine)
+Sulfuric acid
Indigodisulfonic acid, Indigo disodium salt (indigo carmine)
Indigo Retention time: 13.0 min
Retention Indigo carmine time: 4.0 min
Part of a table manufactured by D. Roentgen, 1778, Bavarian National Museum Munich Absorption spectra Green-stained wood (I) Application of Barberry extract + Indigo or Indigo carmine
Wood paneling, Spindler Brothers, 1772-73 The New Chambers Potsdam, Germany
Indigo
Berberine
Green-stained intarsia based on HPLC – Contour plot berberine and indigo carmine Green-stained wood (II) Utilization of wood infected by Chlorociboria sp.(I)
Hyphae of Chlorociboria sp. in wood secreting a green dye
„Xylothek“, Waldenburg, Germany, Xylindein –absoption spectrum and formula 18th century Green-stained wood (III) Utilization of wood infected by Chlorociboria sp.(II)
Wood paneling, Tyrol, 16th century
Intarsia painting, Antonio Violin, Black forest, Barili, San Quirico d‘ Orcia, Germany, 17th century Italy, 1502
Desk, Oslo, Norway, 18th century Grey-or brown-stained wood? Application of iron and nitric acid
Abraham Roentgen David Roentgen (1711-1793) (1743-1807)
Fe + HNO3 + Wood
18th century Today Overview of the identified dyes
Red dyes Blue dyes Brazilin Indigo Carminic acid Indigo carmine Santalin
Yellow dyes Green dyes Apigenin Xylindein Berberine Curcumin
Luteolin Brown dyes Morin Ellagic acid
Inner part of a table for sewing, after 1750, private property Searching for fungus-stained wood utilized for works of art
Chlorociboria sp. Fusarium sp. Ophiostoma sp. „Marble rot“
?
Tunbridge ware Modern wood paneling Medaillon, stained with Ulm cabinet, Ophiostoma sp. Germany,1580 Wibke and Achim Unger
Thank you for your attention
IRG 41st Annual Meeting, Biarritz, France, 09 -13 May 2010