French chalk
Encyclopedia
French chalk is a form of steatite.
As an arist's material the term is used by Max Doerner (Artist)
in his book "The Materials of the Artist" where he describes a calcium carbonate used to make traditional gesso
primer, to be painted over. The favoured chalk used by artists is top quality, 'Champagne Chalk', from the Champagne region of France.
Chalk, calcium carbonate
, dissolves in acids with effervescence (carbonic acid escapes). Chalk is unaffected by alkalis. When heated it remains white. It is not poisonous and has little covering power. Impure samples discolor; for example, when they contain iron, they turn red. When strongly heated, chalk is converted into calcium oxide (quicklime). Oil colors that contain chalk "set" quickly in the tubes. The whiter it is, the more valuable it is. When precipitated it is a very fine material. Gray chalks are not useful in grounds; they develop ugly dark spots when touched by oil.
French chalk was a type of solid talc
bar used by tailors for marking cloth, by cleaners for removing grease
from cloth and as a dry lubricant
in its powdered form.
French chalk has also historically been used in the repair of punctured inner tubes of pneumatic tire
s, such as are found on bicycle
s. A block of French chalk is typically included in proprietary puncture repair kits, which may include some means of generating a fine powder from the block, for example a small file or a roughened area on the metal case in which the repair kit may have been supplied. The French chalk prevents the repair from sticking to other parts of the tire.
As an arist's material the term is used by Max Doerner (Artist)
Max Doerner (Artist)
Max Doerner was a German artist and art theorist.Doerner's artistic education was at the Academy of Fine Arts where he studies under Johann Caspar Herterich and Wilhelm von Diez. His style was basically impressionistic. He travelled around Europe, in particular to the Low Countries and Italy and...
in his book "The Materials of the Artist" where he describes a calcium carbonate used to make traditional gesso
Gesso
Gesso is a white paint mixture consisting of a binder mixed with chalk, gypsum, pigment, or any combination of these...
primer, to be painted over. The favoured chalk used by artists is top quality, 'Champagne Chalk', from the Champagne region of France.
Chalk, calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
, dissolves in acids with effervescence (carbonic acid escapes). Chalk is unaffected by alkalis. When heated it remains white. It is not poisonous and has little covering power. Impure samples discolor; for example, when they contain iron, they turn red. When strongly heated, chalk is converted into calcium oxide (quicklime). Oil colors that contain chalk "set" quickly in the tubes. The whiter it is, the more valuable it is. When precipitated it is a very fine material. Gray chalks are not useful in grounds; they develop ugly dark spots when touched by oil.
French chalk was a type of solid talc
Talc
Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg34 or Mg3Si4O102. In loose form, it is the widely-used substance known as talcum powder. It occurs as foliated to fibrous masses, its crystals being so rare as to be almost unknown...
bar used by tailors for marking cloth, by cleaners for removing grease
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
from cloth and as a dry lubricant
Lubricant
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...
in its powdered form.
French chalk has also historically been used in the repair of punctured inner tubes of pneumatic tire
Tire
A tire or tyre is a ring-shaped covering that fits around a wheel rim to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground...
s, such as are found on bicycle
Bicycle
A bicycle, also known as a bike, pushbike or cycle, is a human-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A person who rides a bicycle is called a cyclist, or bicyclist....
s. A block of French chalk is typically included in proprietary puncture repair kits, which may include some means of generating a fine powder from the block, for example a small file or a roughened area on the metal case in which the repair kit may have been supplied. The French chalk prevents the repair from sticking to other parts of the tire.