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Gums The
natural product can't be beaten
Gums and resins are natural hard substances produced by various trees.
The difference is that resins are only dissolved by solvents like
Turpentine while gums are water soluble and so are suited to water
based paint media. Resins are discussed here.
Related Links:
Oil binders
Acrylic binders
Eggs
Waxes and natural resins
Gum Arabic Gum Senegal,
Kordofan etc.
Also called Gum Acacia in industry, Gum Arabic comes from various
Acacia trees throughout Africa, Asia, and Australia. The best grades
have always come from North Africa. The names Gum Senegal and Kordofan
refer to 2 districts in Africa where the best gum comes from and both
can be regarded as the cream of the crop.
Gum Arabic is the dried sap of the tree which is exuded along cuts made
in the bark, and collected several times a year. The gum is a
protective mechanism on the part of the tree to ward off insect and
fungal invasion and to seal wounds. The healthier the tree the less gum
it produces, production falls with intensive farming methods unlike
most other crops, so small family operations in deprived areas
contribute significantly to world production. When dissolved in water
Gum Arabic has considerable adhesive properties and it finds wide usage
in cosmetics, pharmaceuticals and food production. Artist's use is only
a tiny portion of usage, but to artist's its use is important being the
basis for several paints and drawing materials. Both Watercolors and
Gouache depend on the gum as an ideal binder. It is not however
suitable for thicker paints without the addition of a plasticizer as in
thick layers it can be brittle. Be aware that there are a number of
substitutes used in industry and given the name Gum Arabic that must be
avoided. Chief among these is Gum Gatti, a product of India.
Refined Beeswax has all the impurities removed and then it is poured
into thin slabs that are bleached in the direct sun. The
resulting wax is clear, pure, and has excellent plasticity and melting
temperature that is well suited to Encaustic techniques. Its pale color
is permanent and will not adversely affect colors in any substantial
way.
Cherry gum An interesting
alternative
Both wild and cultivated Cherry Trees exude a clear gum. The gum from
Peach, Plum, Apricot and Almond Trees are said to have similar
qualities. It is sold commercially but some artist's like to use this
gum in the place of Gum Arabic because of the ability to harvest fresh
material locally. The gum should be dissolved by pouring hot water over
it, mashing it and then leaving it to steep over night. It should be
then carefully filtered through cheesecloth. It can be stored if made
into flakes by pouring onto glass and then when hard scraping off.
It was used by Egg Tempera painters and is mentioned by Theophilus. It
is possible that it was widely used instead of Gum Arabic at that time.
it was recorded during Roman times as well. There is no reason to
believe that its use as a binder in Watercolors is problematic.
Gum Tragacanth More suited
to Pastel making
Gum Tragacanth come from shrubs that grow from Iran to Greece. it has
an ancient history, it is the oldest recorded substance used as a drug
ingredient. It is still used by the pharmaceutical industry in pill
making. it also has use as a thickener in sauces and as an emulsifier
in processed foods.. It is the principal binder in the making of Chalks
and Pastels. It is spontaneously exuded on the bark of Astragalus
Gummifer but production is enhanced by making an incision and
driving
in a wooden wedge.
Gum Karaya Gum Arabic
substitute
Gum Karaya comes from a plant that grows in India. It has many
similarities to Gum Tragacanth and can be used as a substitute for it
although only if Gum Tragacanth is unavailable.
References
Alberti, L B, On Painting 1435
(Penguin Classics)
Cellini, B, The Life Of Benvenuto
Cellini, finished 1562 but not published until 1730
(Heron)
Cennini, C d'A, The Craftsman's
Handbook. 1437 (Dover)
Doerner, M, The Materials Of The Artist And Their Use
In Painting, 1921 (Harcourt Brace)
Eastlake, Sir C L, Materials For A History Of Oil
Painting, 1847 (Dover)
Feller, R L, Artists Pigments 1986
(National Gallery Of Art / Cambridge University)
Gottsegen, M D, A Manual Of Painting Materials And
Techniques, 1987 (Harper & Row)
Maire, F, Colors: What They Are And What To Expect Of
Them, 1910 (Drake)
Mayer, R, The Artists Handbook Of Materials And
Techniques, fifth edition 1991 (Faber
& Faber)
Merrifield, Mrs M P, Medieval And Renaissance Treatises On
The Arts Of Painting 1849 (Dover)
Muther, R, The History Of Painting From The Fourth
Century To The Early Nineteenth Century, 1907 (Putnam)
Parkhurst, D B, The Painter In Oil 1898
(Lothrop, Lee & Shepard)
Patton, T C, Pigment Handbook, 1973
(Wiley)
Pliny, The Elder (Gaius Plinius), Natural
History, 77AD (Penguin Classics)
Taubs, F, A Guide To Traditional And Modern Painting
Methods, 1963 (Thames & Hudson)
Theophilus, On Divers Arts, 1125 (Dover)
Various, Encyclopedia Britannica,
fifteenth edition 1981 (Encyclopeadia Britannica, Inc)
Various, Paint And Painting, 1982,
(Winsor & Newton / The Tate Gallery)
Various, The Artist's Colourmen's
Story, 1984 (Winsor & Newton)
Vasari, G, The Lives Of The Most Excellent Painters,
Sculptors And Architects, 1568 (Penguin Classics)
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