Tri-Art Finest Quality Marker - Ultramarine Blue - Broad 27mLUltramarine Blue is a deep, slightly red leaning blue ideal for night skies, shadows, and rich, expressive mixes. In the broad 27 mL acrylic paint marker, it lays down bold, saturated strokes that cover large areas quickly on canvas, paper, and panels. The water based acrylic ink is great for drawing, lettering, and layering over acrylic paintings when you want strong, classic blue with a painterly feel.