In the "I Gotta Feeling" music video by the Black Eyed Peas, the greenish luminous paint that is used is most likely a phosphor-based glow paint. Phosphor glow paints usually consist of a strontium aluminate or zinc sulfide base and are charged using ultraviolet (UV) light sources, making them glow in the dark. These paints are often used for artistic purposes, creating glowing effects in low-light conditions.
To achieve a similar effect as in the music video, you can consider purchasing phosphor glow paints or powders from specialty art supply stores or online retailers. These products come in various colors, including greenish shades. You can mix the paint with a suitable medium or apply it directly to surfaces to create glowing elements.
Ensure proper ventilation when working with phosphor glow paints and always follow the manufacturer's instructions and safety guidelines to ensure a safe and enjoyable artistic experience.