Ragging- A decorative paint finish that is either applied or subtracted with a crumpled damp rag. 

Reaching- (spray gun)- Extending spray stroke too far.

Recoat Time- The period that must elapse between applications of coats of paint.

Reducer- A material which lowers viscosity but is not necessarily a solvent for the particular film former; thinner.

Resin- A natural or synthetic material that is the main ingredient of paint. It binds the ingredients together and improves the coat’s adhesion to the surface.

Roller- A paint application tool consisting of a revolving cylinder covered with fabric, polyester foam, lamb’s wool, etc.

Ropiness-A stringy look to the paint film. Ropiness is a result of the paint not flowing evenly onto the surface.

Runs- Blemishes on the film that are caused by excessive flow of the coating.

Rust Preventive Paint or Primer- The first coat of paint applied directly to iron or steel structures to slow down or prevent rust.