5. Coating consisting of
– Pigments
– a film former (binder)
– a suspending medium or solvent
PAINT
6. Pigments consist of small particles
of colored compounds.
Are derived from finely ground
naturally occurring minerals: rocks
and ores.
These not only give the paint its
colour and finish, but also serve to
protect the surface underneath from
corrosion and weathering as well
as helping to hold the paint
together.
7. Egyptian Blue
It is one of the oldest man-made colors.
Commonly found on wall paintings in Egypt,
Mesopotamia and Rome.
Calcium copper silicate
20. Iron or Prussian Blue
The iron blues are the first of
the artificial pigments with a
known history and an
established date of first
preparation.
The color was made by the
Berlin colormaker in or around
1704.
21. Egg Tempera
Until the 15th century, egg yolk was used as the
most common binder and medium for paints.
Egg tempera is prepared by mixing egg yolks with
a slurry of artist's pigment in water.
Enough water is added to provide the proper
consistency for painting.
22. “BINDS” the pigment and
provides adhesion,integrity and
toughness to the dry paint film.
serves to suspend the pigments
and bind them to the surface of
the object painted.
Examples are: beeswax, linseed
oil, walnut oil, plaster, gum arabic
and egg yolk.
23. Examples of BINDER
Paint technology advanced very little
until this century. Even as recently as
the 1960s 'drying oils' were the
commonest paint binders.
Linseed oil, the most common example
of a drying oil, will dry in 2 to 3 days
while other oils, such as soya bean oil,
may take up to 10 days.
24. PVCPVC
Pigment volume (not weight) concentration
It use to determined
the quality of paint
25. Functions oF pigment and
binder in paint
FILM FORMATION of latex paint occurs
when the paint is applied and the water
evaporates. During this process, the
particles of pigment and binder come
closer together.
As liquid evaporate, capillary
action draws the binder particles together
with great force, causing them to fuse and
bind the pigment into a continuous film.
26. Functions oF pigmentFunctions oF pigment
The pigments are used in paint formulation to
carry out one or more of the following tasks:
i. to provide color,
ii. to hide substrates and obliterate previous colors ,
iii. to improve the strength of the paint film,
iv. to improve the adhesion of the paint film,
v. to reduce gloss,
vi. to reduce cost
27. Functions oF pigments
1. To protect the film by reflecting the destructive uv ray
2. To Provides surface protection and decoration.
3. They are non toxic and most of all chemically inert.
4. to make paint hard and sensitive.
5. To make surface attractive by providing unique color.
28. Fuctions oF binder
The binder is a very important ingredient that
affects almost all properties of the coating,
especially the following…
adhesion and related properties like resistance to
blistering, cracking and peeling
other key resistance properties like resistance to
scrubbing, chalking and fading
application properties like flow, leveling and film build,
and gloss development
29. Functions oF pVc
The pvc largely controls such factors as-
Gloss
Reflectance
Rheological properties
Wash ability
Durability
It also serves as the guide for reformulation
work, using different pigment or vehicle
combination and such is extremely useful to
the pant formation.
31. WISH you…. Have a
coLourFuLL LiFecoLourFuLL LiFe
with Happiness…
Editor's Notes
Egyptian blue ("frit," "Pompeiian blue"):
Origin and History: Very stable synthetical pigment of varying blue colour. It is one of the oldest man-made colors commonly found on wall paintings in Egypt, Mesopotamia and Rome. Many specimens, well over 3000 years old, appear to be little changed by the time.
Making the Pigment: Heating a mixture of a calcium compound (carbonate, sulfate or hydroxide), copper compound (oxide or malachite) and quartz or silica gel in proportions that correspond to a ratio of 4 SiO2 : 1 CaO : 1 CuO to a temperature of 900°C using a flux of sodium carbonate, potassium carbonate or borax. The mixture is then maintained at a temperature of 800°C for a period ranging from 10 to 100 hours.
Chemical Properties: Calcium copper silicate, CaCuSi4O10. It is insoluble in acids even in warm temperatures.
Artistic Notes: It has a discreet covering power. It can be used in fresco. Not advised in tempera, oil and encaustic.
Egyptian Makeup Pot
Both men and women used special powders and pastes to cover their skin. The make-up was not only worn to make them look attractive but also to protect them from the hot climate - quite similar to how we use sun cream today.This pot may have stored 'Khol' - black makeup that the Egyptians used to decorate their eyes.
Vermilion ("Cinnabar"):
Vermilion is the standard name given to the red pigment based on artificially-made mercuric sulfide. The common red crystalline form of mercuric sulfide is cinnabar, a name reserved only for the natural mineral. The natural product found chiefly in Almaden and Idria has been eliminated for practical purposes (including that it is slightly poisonous).
The synthesis of these mercury and sulphur into cinnabar is accomplished by mixing them together and heating them; if simply mixed and ground together, a black sulfide of mercury is formed, but at the proper temperature this vaporizes and recondenses in the top of the flask in which it is heated. The flask is then broken and the vermilion is removed and ground. Upon grinding the red color begins to appear, and the longer it is ground, the finer the color becomes. This process was understood before the year 800 AD.
The properties of both natural and artificially prepared are practically identical. Cinnabar, a dense red mineral, is the principal ore of mercury or quicksilver. Vermilion is not generally considered today to be a permanent pigment. It has been known since Roman times that specimens of vermilion darken when exposed to light. In tests it has been discovered that impurities in the alkali polysylfides used to "digest" the pigment, leading to the instability of the red. This catalyzes the transition of the red to black. Also, we've found that the darkening of vermilion occurs mainly in paintings in egg tempera but it is not unknown in oil paintings. It is however fairly unreactive to other colors' chemical makeups; therefore, when mixed with lead white to produce flesh tones, it did not produce the black sulfides.
Burnt Sienna:
Making the Pigment: Burnt sienna is prepared by calcining raw sienna which in the process undergoes a great change in hue and depth of color; in going from ferric hydrate of raw earth to ferric oxide, it turns to a warm, reddish brown.
Chemical Properties: Fe2O3 * nH2O + Al2O3 (60%) Manganese dioxide (1%), calcined natural iron oxide (PBr 7). Microscopically, heating makes the pigment more even in color and the grains are reddish brown by transmitted light.
Artistic Notes: Because of its transparency, burnt sienna is used as a fiery glazing color which requires much binder, about 180%, and as an oil color is apt to jelly. This is remedied by washing, which however dilutes the intensity of the color. In 1768, Martin Knoller stated that very strong heat will produce a sienna resembling vermilion that may be used in fresco out of doors. American Burnt Sienna is a strong type of ochre and is neither as clear nor as brilliant as the Italian Sienna. It supposedly imparts a muddy tone but is very permanent in all techniques.
Roman Cosmetics
Roman women used ground chalk or lead to make their faces look white. Pale skin was very fashionable. It was a sign that a woman was rich enough not to have to work outdoors in the fields.
Eyeliner was popular to make the eyes look bigger. It was made from a mixture of soot and olive oil.
Metal scoops were used to mix make-up in small dishes.
Roman Cosmetic Box
Cosmetic box with carved bone deco
Naples, Archaeological Museum, 1st century CE
Roman Cosmetic Secrets Revealed
The fashion conscious women of Roman Britain used a tin-based foundation to get a pale and appealing look.
The evidence comes from a sealed pot of ointment found at an archaeological dig in Southwark, south London in 2003.
Bristol University scientists analyzed the cream and found it to be made from animal fat, starch and tin oxide.
Zinc white ("Chinese white," "silver white"):
Origin and History: First introduced in 1840, this white is colder in appearance than lead white, and doesn't cover nearly as well, yet it is far less expensive. Zinc has been known as a mineral since antiquity when it was melted with copper to form brass. It was also known then, as it is today, as a medicinal ointment. In 1782, zinc oxide was suggested as a white pigment. Guyton de Morveau at L'Académie de Dijon, France, reported zinc oxideas a substitute for white lead. Metallic zinc had originally come from China and the East Indies. When zinc ore was found in Europe, large-scale production of the extracted metallic zinc began. In 1834, Winsor and Newton, Limited, of London, introduced a particularly dense form of zinc oxide which was sold as Chinese white. It was different from former zinc white in that the zinc was heated at much higher temperatures than the late eighteenth century variety. By 1844, a better zinc white for oil was developed by LeClaire in Paris. He ground the zinc oxide with poppy oil that had been made fast drying by boiling it with pyrolusite (MnO2). In 1845, he was producing the oil paint on a large scale.Making the Pigment: The French method of manufacturing, known as the 'indirect process' used the zinc smoke derived from molten zinc, which was heated to 150°C and collected in a series of chambers.
Chemical Properties: Zinc oxide, ZnO. If you heat zinc white, it turns to lemon yellow, but will revert to white when cooled. It differs from lead white in this respect. Since zinc oxide is derived from smoke fumes, its particles are very fine and are difficult to observe except at very high magnification. It readily dissolves in alkaline solutions, acids and ammonia without foaming.
Artistic Notes: It is non-poisonous, permanent and doesn't yellow, though these factors are true only with pure zinc white. It also disintegrates quickly out of doors, and increases in volume causing massive crackling, so it is not useful in fresco. Ground in oil it dries slowly, especially in poppy oil, where the retarded drying time is needed. It does not dry as solid as lead white, due to some transparency in the pigment. A small addition of damar or mastic varnish speeds up the drying time. As it is very fine in powder form, it can be sufficiently mixed with only a spatula, requiring 30% binder and an addition of 2% wax in the tube to prevent hardening. It is compatible with all other pigments, including copper-based, but in watercolor it is destructive to the permanency of coal-tar colors and accelerates the process of fading (though it doesn't do this in oil.) Zinc is essentially permanent in sunlight although the yellowing in oil affects its brightness. It is neither as opaque nor heavy as lead white and it takes much longer to dry. Because zinc white is so "clean" it is very valuable for making tints with other colors. Tints made with zinc white show every nuance of a color's undertones to a degree greater than tints made with other whites, and the artist has time to complete his work before the paint dries. Despite its many advantages over lead white, zinc white oil color also has a drawback; it makes a rather brittle dry paint film when used unmixed with other colors. Zinc whites' lack of pliancy can cause cracks in paintings after only a few years if this color is used straight up to excess.
Vine Black:
Charcoal made from young shoots of grape vines were referred to in medieval times as the best of blacks. It is now referred to as more of a blue-black, considering the coolness of the grays that it produces in mixtures.
It is important that the vine sprigs be thoroughly burnt and reduced to carbon, otherwise the color will be brownish and an unpleasant consistency; but they must not be burnt in the air or they might reduce to ashes instead of to carbon. They are packed tightly in little bundles in casseroles, covered and sealed, and baked in a slow oven. You can make your own vine black with a similar method. The resulting charcoal is used in sticks for drawing; for painting it is first powdered and ground up dry, and then mixed with water and ground for a long time between two hard stones.
This paint dries extremely rapidly, and when applied thinly, it gives a translucent glaze that allows either a white surface ground or an undercoat to show through.
The drying and hardening process of the medium involves the both the denaturation of the proteins from the egg and polymerization of the fats in the yolk.
The proteins form many hydrogen bonds with each other and with the surface, locking the pigments into a solid matrix. As they age, these proteins form covalent bonds with each other, making the matrix very stable and permanent.
Binders
Paint technology advanced very little until this century. Even as recently as the 1960s 'drying
oils' were the commonest paint binders. Drying oils are substances that, when spread out in a
film, will dry to form a continuous skin. Linseed oil, the most common example of a drying
oil, will dry in 2 to 3 days while other oils, such as soya bean oil, may take up to 10 days.
FILM FORMATION of latex paint occurs
when the paint is applied and the water
evaporates. During this process, the particles of
pigment and binder come closer together. As
the last vestiges of liquid evaporate, capillary
action draws the binder particles together
with great force, causing them to fuse and
bind the pigment into a continuous film. This
process, called coalescence, is depicted in the
following graphic. On the other hand, latex paints may blister
from rain, dew or other sources of water on
the outside of the coating, if the paint:
• has limited adhesion capability
• was applied over a chalky or otherwise
unclean surface, such that the paint’s
adhesion was compromised
• has not had enough time to dry thoroughly
