Here's why he used bold outlines:
* Emphasis and Clarity: The black lines emphasized the graphic nature of his work, clearly defining shapes and figures. This made his paintings visually striking and easily recognizable.
* Ben-Day Dots: Lichtenstein's use of Ben-Day dots, a printing technique, was another defining characteristic of his style. The bold outlines helped to further separate the dot patterns and create a visually distinct surface.
* Pop Art Aesthetics: Lichtenstein's bold outlines reflected the graphic nature of mass media, advertising, and comic books, which were central to the Pop Art movement.
* Color Contrast: The black lines often contrasted with the bright, vibrant colors he used in his paintings, adding depth and dimension to his artwork.
It's important to note that Lichtenstein experimented with various colors and techniques throughout his career. He did use outlines in colors other than black, sometimes even incorporating white or bright colors, but black remained his signature choice.
Overall, the bold outlines were an integral part of Lichtenstein's signature style, contributing to the iconic and instantly recognizable aesthetic of his Pop Art.