Ancient binding media, varnishes and adhesives

124 Pages·2014·4.41 MB·English

ANCIENT BINDING MEDIA,
VARNISHES AND ADHESIVES
Liliane Masschelein-Kleiner
Translated by
Janet Bridgland
Sue Walston
A.E. Werner
ICCROM
Rome, 1995
Editor's note: The place names included in this volume are not necessarily a reflec-
tion of current geopolitical reality, but are based on the historical trade names under
which various products and substances have come to be known.
This second edition of Ancient Binding Media, Varnishes and Adhesives is based
on the third French edition of Liants, vernis et aditesifs anciens, published in 1992
by the Institut Royal du Patrimoine Artistique, Brussels — ISBN 20930054-01-8.
The English edition, with the addition of an index, was prepared by ICCROM,
which is responsible for the scientific quality of the translation.
ISBN 92-9077-119-4
© 1995 ICCROM
ICCROM — International Centre for the Study of the
Preservation and Restoration of Cultural Property
Via di San Michele 13
1-00153 Rome RM, Italy
Printed in Italy by A & J Servizi Grafici Editoriali
Cover design: Studio PAGE
Layout: Cynthia Rockwell
Technical editing, indexing: Thorgeir Lawrence
CONTENTS
INTRODUCTION (cid:9) vii
Chapter 1. PHYSICAL AND CHEMICAL PROPERTIES
OF FILM-FORMING MATERIALS
I. LIQUID STATE (cid:9) 1
Definitions: solution, dispersion, emulsion (cid:9) 1
I. 1 Surface phenomena and wetting (cid:9) 2
I. 2 Stabilization of pigments (cid:9) 5
I. 3 Rheological properties (cid:9) 6
I. 4 Oil index and critical concentration (cid:9) 10
II. SOLID STATE (cid:9) 12
II. 1 Film formation (cid:9) 12
II. 1. 1 Film formation by physical change (cid:9) 12
II. 1. 2 Film formation by chemical reaction (cid:9) 15
II. 2 Optical properties (cid:9) 17
II. 2. 1 Gloss (cid:9) 17
II. 2. 2 Opacity - hiding power (cid:9) 19
II. 2. 3 Colour (cid:9) 22
II. 3 Mechanical properties (cid:9) 25
II. 3. 1 Permeability - porosity (cid:9) 25
II. 3. 2 Toughness (cid:9) 26
II. 3. 3 Flexibility (cid:9) 27
II. 3. 4 Adhesive power (cid:9) 29
iv
Chapter 2. DESCRIPTION OF THE MAIN NATURAL FILM-FORMING MATERIALS
I. LIPIDS OR FATTY MATERIALS (cid:9) 33
I.1 Normal saturated fatty acids (cid:9) 33
1.2 Unsaturated fatty acids (cid:9) 34
1.3 Hydroxy acids (cid:9) 34
A. GLYCERIDES (cid:9) 35
ANIMAL FATS - TALLOW (cid:9) 36
VEGETABLE FATS (cid:9) 36
DRYING AND SEMI-DRYING OILS (cid:9) 36
Linseed oil (cid:9) 37
Poppy oil (cid:9) 39
Nut oil (cid:9) 39
Egg-yolk oil (cid:9) 39
B. WAXES (cid:9) 40
MINERAL WAXES (cid:9) 41
Paraffin and microcrystalline waxes (cid:9) 41
Montan wax (cid:9) 42
Ozocerite (cid:9) 42
Ceresin (cid:9) 42
VEGETABLE WAXES (cid:9) 42
Candelilla wax (cid:9) 42
Carnauba wax (cid:9) 43
ANIMAL WAXES (cid:9) 43
Beeswax (cid:9) 43
Chinese wax (cid:9) 44
Spermaceti wax (cid:9) 44
Lanolin (cid:9) 44
C. STEROIDS (cid:9) 45
Cholesterol (cid:9) 45
Vegetable sterols (cid:9) 45
Saponins (cid:9) 46
II. CARBOHYDRATES, PARTICULARLY SUGAR COMPOUNDS (cid:9) 46
A. POLYSACCHARIDE GUMS (cid:9) 49
Gum arabic or acacia gum (cid:9) 49
Gum tragacanth (cid:9) 50
Fruit tree gums (cid:9) 51
v
B. VEGETABLE MUCILAGES (cid:9) 51
Starches (cid:9) 51
Dextrins (cid:9) 53
Galactomannans (cid:9) 53
Glucomannans (cid:9) 54
C. CELLULOSE DERIVATIVES (cid:9) 54
Cellulose nitrate (cid:9) 55
Cellulose acetate (cid:9) 55
Cellulose ethers (cid:9) 55
III. PROTEINS OR ALBUMINOUS MATERIALS (cid:9) 56
Gelatin and animal glue (cid:9) 57
Fish glues (cid:9) 58
Casein (cid:9) 59
Eggwhite (cid:9) 60
Egg-yolk (cid:9) 61
Temperas - Distempers (cid:9) 61
IV. TERPENES OR RESINOUS MATERIALS (cid:9) 64
A. and B. MONO- AND SESQUITERPENES (cid:9) 67
Oil of turpentine (cid:9) 67
Oil of spike or aspic (cid:9) 67
A. B. and C. MONO-, SESQUI- AND DITERPENES (cid:9) 68
Venice turpentine (cid:9) 68
Strasbourg turpentine [Alsatian; Strasburg] (cid:9) 68
C. DITERPENES (cid:9) 68
Rosin (colophony) (cid:9) 68
Sandarac (cid:9) 70
Copals (cid:9) 70
D. TRITERPENES (cid:9) 72
Dammars (cid:9) 72
Mastic (cid:9) 73
Elemi (cid:9) 74
V. RESINOUS MATERIALS NOT (exclusively) TERPENES (cid:9) 74
Benzoin (cid:9) 74
Balsam of Peru (cid:9) 74
Balsam of Tolu (cid:9) 75
vi
Copaiba balsam (cid:9) 75
Dragon's blood (cid:9) 75
Amber (cid:9) 76
Lacquer of the Far East or true lacquer (cid:9) 76
Lac, gum lac or shellac (cid:9) 77
VI. EMPYREUMATIC MATERIALS: TARS, BITUMENS (cid:9) 78
A. TARS (cid:9) 78
Vegetable tar - Wood tar (cid:9) 78
Animal tar (cid:9) 79
Coal tar (cid:9) 79
B. BITUMENS (cid:9) 79
REFERENCES (cid:9) 81
BIBLIOGRAPHY (cid:9) 91
INDEX (cid:9) 101
INTRODUCTION
The materials used as binding media, adhesives and varnishes are all film-form-
ing substances. These are liquid plastic materials that are capable of forming a solid
skin called a film when applied in a thin layer on several materials that are called
substrates [1].
The use of film-forming materials is doubtless as old as man himself. Neverthe-
less, the history of the discovery of these materials is not well known. Ancient technical
treatises are rare and often difficult to translate. The terms used to describe the materials
are imprecise and sometimes they have changed their meaning in the course of time.
A comprehensive review of these treatises was published in 1969 by Alexander [2].
Modern methods of analysis are gradually revealing more detailed information
about ancient techniques [151, 152, 153, 157, 178]. Still, many unanswered questions
remain; these include, for example, the date when oil painting first came into use [3,4],
the composition of the well-known binding media of the Flemish Primitives [5], the
nature of the varnish used in the past for musical instruments, etc.
This book will deal with the physical and chemical properties of film-forming
materials. Knowledge of their properties will help conservators understand phenomena
encountered in their work that would otherwise be difficult to master.
The principal characteristics of the natural film-forming materials used in the
past will then be discussed.