an acid changes the color of litmus paper from blue to red
coloring is not change_of_color. red is color. color_pink has red_and_white_factors blackening is change_of_color. coloring is change_of_color. color_pink has not red_and_white_factors change_of_color is change_of_state. change_of_color is not change_of_state. litmus is acid_base_indicator. litmus is not acid_base_indicator.