Creating a captivating rainbow makeup look can sometimes feel overwhelming due to the number of brushes and products typically involved. However, using just one brush can simplify the process and make it accessible to everyone. From my experience, the key is to choose a highly pigmented eyeshadow palette, like the ColourPop Fade Into Hue palette mentioned here, which offers a smooth gradient of rainbow colors that blend effortlessly. I recommend starting with a clean, moisturized eyelid and applying a light base using a primer or a blur-on setting powder like the one from Hard Candy. This ensures that the eyeshadow stays put and the colors remain vivid throughout the day. Using a single, fluffy blending brush allows you to pick up multiple hues gently, layering them from one corner of the eyelid to the other to create a seamless rainbow effect without harsh lines. Pairing the eyeshadow with a tinted lip product such as the Milk Makeup jelly tint provides a natural, fresh finish that complements the vibrant eye look without overpowering it. Finishing touches with a chrome lipstick from Unearthly Cosmetics can add that perfect pop of shine and dimension to your lips, balancing the overall makeup. This technique is ideal for summer events, festivals, or whenever you want your makeup to be the center of attention with a playful yet polished vibe. Remember, blending is key to achieving the dreamy rainbow gradient, so take your time and enjoy the process. Don't hesitate to experiment with different brush sizes or slightly layering products to match your personal style and preferences. Embrace creativity and have fun with this one brush rainbow makeup approach!