Matisse was also one of the first 20th-century artists to make color the central element of the painting, chosen to evoke emotions. "A certain blue penetrates your soul", he wrote. "A certain <answer>red</answer> affects your blood pressure." He also was familiar with the way that complementary colors, such as <answer>red</answer> and green, strengthened each other when they were placed next to each other. He wrote, "My choice of colors is not based on scientific theory; it is based on observation, upon feelings, upon the real nature of each experience ... I just try to find a color which corresponds to my feelings."
What color did Matisse claim would impact ones blood pressure?
red