Abstract: The present invention provides a colored masking liquid composition, and a method of masking a paint spray booth, wherein the composition comprises one or more polymers dispersed or dissolved in water, a base in a sufficient amount to provide a pH greater than 7, and a pH indicator that is colored at the pH of the masking liquid composition. Applying the colored masking liquid composition to the interior surface of a spray booth and allowing to dry results in a colorless mask.

Abstract: The present application discloses a method of masking an interior surface of a spray booth, the method comprising: —providing a masking liquid comprising one or more polymers dispersed or dissolved in water, a base in amount sufficient to such that the pH of the masking liquid is more than 7 and a pH indicator that is colored at the pH of the masking liquid; —applying the masking liquid to at least part of an interior surface of the spray booth; —allowing the applied masking liquid to dry whereby upon drying the pH indicator becomes colorless or substantially colorless and a clear transparent or translucent white masking coating is obtained.