Rainbow paint in the Roblox game is typically a premium feature, but you can achieve rainbow effects through creative techniques or by participating in specific community events. Methods for Rainbow Effects

You can simulate a rainbow by manually overlapping different colors from the RGB spectrum. Using lower opacity settings and overlapping strokes creates a smooth, gradual transition between colors, similar to a rainbow ombre effect.

While direct "Rainbow Paint" often requires a purchase, players use these workarounds to get the look for free:

Use this to quickly sample and reuse colors from other rainbow artworks to maintain a consistent palette.

Be careful with non-opaque paint; using too much can cause the game to automatically disable it to maintain performance.