Chemistry: Indicators - pH paper, litmus paper, and phenolphthalein

Litmus paper 

 Has a special dye on it that changes colors in the presence of an acid or base. 

 Blue litmus paper turns red in an acid, and stays blue in a base. 

 Red litmus paper turns blue in a base, and stays red in an acid. 

Phenolphthalein 

 Is used to test for the presence of a base. 

 It is a colorless chemical that turns magenta (bright pink) in a base, and stays colorless in neutral or acidic solutions. 

pH paper

Has a range of colors depending on the pH of the solution. 

 The color of the paper is compared to the chart on the vial to determine the pH.