Stained woodThe 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

plants

animals

fungi

Coal tar dyes

Aniline dyes

Azo dyes

Anthraquinone dyes

Sulfur dyes

Nitro and nitroso dyes

Rasped natural - colored wood and roots

Historic packaging for methyl violet

Dyestuffs of vegetable origin

Wood

Bark

Fruits

Leaves

Roots

Flowers

Seed

Lichen

Old fustic, Brazil wood

Common buckthorn

Indigo plant

Madder, Turmeric

Safflower

Annatto

Orchella weed

Black oak

Dyestuffs of animal origin

Insects Marine snails Cuttle fish

Tyrian PurpleKermes, Lac-insect, Cochineal

Sepia

Peter-Paul Rubens

The dog of the Phoenician godMelqart discovers the spiny dye-

murex

Dyestuffs of fungal origin

Pynoporus cinnabarinus

Chlorociboria sp.

Phanerochaete sanguinea

Pulcherricium caeruleum

Cinnabarin

Xylindein

Terphenols

Xylerythrines

„Mycodyes“

Classification of natural dyes based on the dyeing method

Natural dyes

Mordant dyes Direct dyes Vat dyes

Pre-treatment of fibermaterial with metal

salts

Dyeing of fibermaterial without

pre-treatment

Soaking of fiber mate-rial into a solution of the

reduced dye. After removal from the vat

oxidation to the real dye on the material

Examples Examples Examples

Alizarin

Brazilin

Carminic acid

Berberine

Carthamin

Curcumin

Indigo

TyrianPurple

Analytical procedures for identification of dyes and mordants

Methods

Dyes Mordants

UV/Vis spectrometry (UV/Vis)

3D fluorescence spectrometry

High-performance liquid chromatography (HPLC)

X-ray fluorescence

spectrometry (XRF)

Atomic emission spectrometry (AES)

Non-destructive

Destructive

Thin layer chromatography (TLC)

Red-stained wood (I)Application of extracts from Brazil wood

Brazil wood (Caesalpinia sp.) Shutter cabinet, David Roentgen, 1773

Parquet flooring, Spindler Brothers, 1765 Brazilin – absorption spectrum and formula

American Cochineal (Dactylopius coccus) on the nopal cactus

Red-stained wood (II)Application of extracts from Cochineal

Toilet table, Abraham Roentgen, 1765

Rose intarsia stained with

cochineal extractCarminic acid –absorption spectrum and formula

Yellow-stained wood (I)Application of extracts from European barberry

European barberry(Berberis vulgaris)

Maple intarsia yellow-stained withan extract from barberry wood

Augsburg cabinet, 1560/70

Berberine – absorption spectrum and formula

Barberry wood

„The Holy Rochus“,marquetry painting,

Spindler Brothers, 1770

Turmeric (Curcuma longa)

Yellow-stained wood (II)Application of extracts from Turmeric

Reverse side of curcuma-

stained intarsia

Wood paneling, SpindlerBrothers, 1765-68

Curcumin – absorption spectrum and formula

Indigo plant (Indigofera tinctoria)

Preliminary stage: Indican

Woad (Isatis tinctoria)

Preliminary stage: Isatan B

Distribution map of indigo species

Blue-stained wood (I)Application of Indigo (I)

Woad mill in Thuringia, Germany, 1910

Woad ball

Blue-stained wood (II)Application of Indigo (II)

Woad Indigo plant

Leaves dried on

Indigo dye balls

Indican or Isatan B

Fermentation

Indoxyl (+ Glucose)

Air

Indigo

Blue-stained wood (III)Application of Indigo (III)

Leuco - IndigoIndigo

Tyrolese cabinet , around 1630, Grassi-Museum Leipzig, Germany

Blue-stained wood (IV)Application of Indigo (IV)

Shavings stained with indigo

Part of a table manufactured by D. Roentgen, 1778, Bavarian National Museum Munich

Blue-stained wood (V)Application of Indigodisulfonic acid (Indigo carmine)

+ Sulfuric acid

Indigodisulfonic acid,

disodium salt (indigo carmine)Indigo

Indigo

Indigo carmine

Absorption spectra

Retention time:

4.0 min

Retention time:

13.0 min

Green-stained wood (I)Application of Barberry extract + Indigo or Indigo carmine

The New Chambers Potsdam, Germany

Wood paneling, Spindler Brothers,

1772-73

Green-stained intarsia based on berberine and indigo carmineHPLC – Contour plot

Berberine

Indigo

Xylindein – absoption spectrum and formula

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, 18th century

Wood paneling, Tyrol, 16th century

Violin, Black forest, Germany, 17th century

Green-stained wood (III)Utilization of wood infected by Chlorociboria sp.(II)

Intarsia painting, Antonio Barili, San Quirico d‘ Orcia,

Italy, 1502

Desk, Oslo, Norway, 18th century

Abraham Roentgen (1711-1793)

David Roentgen (1743-1807)

Fe + HNO3 + Wood

Grey- or brown-stained wood?Application of iron and nitric acid

18th century Today

Overview of the identified dyes

Inner part of a table for sewing, after 1750, private property

Red dyes

Brazilin

Carminic acid

Santalin

Yellow dyes

Apigenin

Berberine

Curcumin

Luteolin

Morin

Blue dyes

Indigo

Indigo carmine

Green dyes

Xylindein

Brown dyes

Ellagic acid

Searching for fungus-stained wood utilized for works of art

Fusarium sp. Ophiostoma sp.Chlorociboria sp. „Marble rot“

Tunbridge ware Modern wood panelingstained with

Ophiostoma sp.

Medaillon, Ulm cabinet,

Germany,1580

?

Thank you for your attention

IRG 41st Annual Meeting, Biarritz, France, 09 -13 May 2010

Wibke and Achim Unger