CALCIUM CARBONATE:
A mined material (chalk) that is used as an extender or filler for paint and sealant.

CHALKING:
Deterioration of the surface of an exterior paint upon weathering into a faded, powdery substance. Chalking occurs when the paint's binder is degraded by harsh environmental conditions. Chalk should be removed prior to repainting.

CHECKING:
Patterns of short, narrow breaks in the top layer of paint. Checking occurs when the paint loses its elasticity.

CHEMICAL RESISTANCE:
The ability of a coating to resist damage by chemicals.

CHIME:
The lip around the opening of a paint can into which the lid is placed.

CLAY:
A white, mined mineral used as an extender - mostly in interior paints.

COALESCENT:
An organic solvent used in acrylic paints that acts as a temporary plasticizer, to aid in film formation. It helps the binder form a continuous film when applied, particularly at the low end of the application temperature range recommended for the coating.

COATING:
A paint, stain, varnish, lacquer, or other finish that provides a protective and/or decorative layer over a substrate.

COLOUR RETENTION:
The ability of a paint to keep its original colour and resist fading. This term is generally applied to exterior paints.

COLOUR WHEEL:
A circular chart with wedge-shaped segments of different specific colours. Used in colour decorating.

COLOURANT:
A concentrated liquid or dry colour that is added to a paint to obtain a chosen color.

COLOURFAST:
The ability to maintain colour and not fade excessively under normal conditions.

COMBUSTIBLE:
Refers to any liquid with a flash point at or above 100oF (37.50C).

COMPLEMENTARY COLOURS:
Two colors directly opposite one another on the color wheel.

CONSISTENCY:
The thickness or brushability of a paint.

CONTRASTING COLOURS:
Colours separated by at least three others on the color wheel.

CORROSION INHIBITOR:
Any material used to prevent the oxidation (rusting) of metals. May be a paint undercoat, an additive, a pigment, or a coating applied to the surface.

CORROSION-RESISTANT:
Ability of a substance to resist deterioration due to a chemical reaction with its environment. Coatings that do this usually contain a corrosion inhibitor.

COVERAGE:
The spread rate of a paint or coating, usually expressed in sq. ft./gal. or m2/l. With pigmented coatings, it can refer to applied hiding power.

CRACKING:
The splitting of a dry paint or varnish film, usually a result of aging or movement of the substrate. Different forms are hair-line cracking, checking, crazing, grain cracking, or crocodiling.

CROCODILING:
A scaly pattern that appears on paint due to the inability of the paint to bond to a glossy coating beneath it. It can also be due to the application of a hard coating over a soft primer, or (with oil-based paint) because the wood was recoated before the undercoat was dry.

CRYSTALLINE SILICA:
See Silica.

CUSTOM COLOUR:
Special colours that are made by adding colourant to paint or by intermixing paints of different colours. Permits the preparation of a selected colour paint at the point of sale.

CUTTING IN:
The painting of a surface adjacent to another surface that must not be painted. For example, painting the frame of a window but not the glass.