Folklore has it that ambient color has the power to relax or arouse the observer and enhance performance when executing cognitive tasks. We picked a number of commercially available colors that allegedly have the power to alter cognitive performance and the emotional state, and exposed subjects to them while solving a battery of cognitive tasks. The colors were Cool Down Pink, which is said to produce relaxing effects and reduce effort, Energy Red, allegedly enhancing performance via increased arousal, Relaxing Blue, which is said to enhance attention and concentration, as well as white as a control. In a between-subjects design, a total of 170 high school students carried out five tasks (number series completion, mental rotation, and memory for word categories, word pairs, and geometrical figures) while exposed to one of the four colors. The emotional state of the subjects was measured before the beginning and at the end of the experiment. The ambient colors did not have the predicted effects, neither on cognitive performance nor on the emotional state of the participants.