Liquitex - Artist Acrylic Effects Fluid Medium - Iridescent Medium - 8 oz - Liquitex Iridescent Medium Fluid Medium adds richness to acrylic colors by creating a metallic and pearlescent effect. Dries translucent and will not oxidize. Adds shimmer or sparkle to a picture even in the smallest amount. Achieve the most dramatic effects when mixing with transparent colors. Try painting on top of any dry color for unique effects.