Uni Posca Marker PC-3M, Fine 1.3 mm

The POSCA PC-3M has a 0.9–1.3 mm bullet tip, sized to handle both outline work and filling in smaller color blocks without switching pens — sharp enough for detailed illustration lines or sneaker designs, broad enough to lay down a solid color fill without leaving streaks. It's filled with a water-based acrylic paint rather than a dye or pigment ink, which is what gives it full opacity: light colors cover dark backgrounds cleanly in a single pass instead of mixing into a muddy in-between shade, the way a transparent marker would.

Because it's a true paint rather than ink, POSCA works on surfaces that absorb or reject standard markers altogether — canvas, ceramics, glass, leather, skateboards, stone, even plastic — without bleeding through paper the way alcohol markers do. It's become a particular favorite for rock painting, where the paint sits opaque and bright in the uneven pores of a stone surface rather than soaking in unevenly. The paint dries permanent and water-resistant once cured, though for anything staying outdoors long-term — painted rocks, terracotta pots, garden signs — a clear spray varnish over the finished piece adds real UV and weather protection on top of that.

The tip itself is removable and washable: if it dries out or picks up another color, you can pull it, rinse it under a tap, and put it back in. Before first use, the marker needs a firm shake to mix an internal ball with the paint, then some priming on scrap card to get the valve-action flow started.

Specifications

• Tip: 0.9–1.3 mm fine bullet, polyester, removable and washable
• Ink: water-based acrylic paint, opaque, odorless, non-toxic, lightfast, acid-free
• Surfaces: paper, canvas, ceramic, glass, leather, skateboards, stone, plastic, and more
• Setup: requires shaking and tip-priming before first use

You can find more POSCA products here.