Casein Paint- Water thinned paint with vehicle derived from milk.

Catalyst- An ingredient that speeds up a chemical reaction. Catalysts are sometimes used in two-component epoxy systems.

Cat Eye- Hole or holiday shaped like a cat’s eye, cratering.

Caulk- A flexible (semi-drying or slow-drying) mastic compound used to seal joints or fill crevices around windows, chimneys, etc., prior to or after painting.

Caulking Gun- A tool for expelling caulk from a tube. It enables a “bead” of material to be applied to cracks and seams.

Chalking- Loose powder forming on the surface of a paint after exposure to the elements.

Checking- A kind of paint failure in which many small cracks appear in the surface of the paint.

Coalescing- The flowing or melding together of emulsion particles when a latex paint dries.

Coating- A general term referring to any type of paint, stain, etc.

Coating System- Paint products used together to cover the same surface. The film may be the result of primer, undercoat and topcoat (also called finish coat).

Cohesion- The ability of a coating to hold together (the attraction of molecules within the coating).

Cold-Cracking- Cracking occurring at low temperatures.

Colorfast- Non-Fading.

Color Chip- A color sample usually consisting of a paint applied to a small piece of card (a chip).

Colorant- Colored pigment added in small proportions to prepared paints to tint them.

Color Washing- A technique used to build up layers of diluted paint to produce depth and textural interests.

Combing- A technique of pulling a toothed (comb) through wet paint.The comb can be made of a material such as: rubber, metal, leather, plastic or cardboard.

Combustible- Able to burn.

Consistency- Viscosity.

Coverage- The area over which a given amount of paint will spread and completely hide the surface. Coverage, also known as spreading rate, is normally expressed in square feet per gallon or in square metres per litre.

Cracking- Breaks in the paint film wide enough to expose the underlying surface.

Crackle Finish- Crackle finishes have an aged, weathered look, resembling cracked glass.

Crawling- Shrinking of paint to form uneven surface.

Crazing- Small interlacing cracks in the paint film.

Cross Spraying- Spraying first in one direction and second at right angles.

Curtaining- Sagging

Cutting-In- The brushing technique that is used when a clean, sharp edge is needed. Cutting-in is needed, for example, for a window sash (using a sash brush), the top of a wall where it meets the ceiling, and in areas that are hard to reach (especially when using a roller).