Posca markers explained: tips, surfaces and which to buy
Posca markers have a loyal following among artists, crafters and students. They are different from most markers in some important ways. Here is what makes them useful and how to get the most out of them.
What is a Posca marker?
Posca is a paint marker made by Mitsubishi Pencil Company. Unlike standard permanent markers which use solvent-based dye ink, Posca uses water-based paint. This means the ink is opaque: it covers what is underneath it rather than just staining the surface. White Posca on black card, for example, looks clean and solid rather than grey or washed-out.
The water-based formula also means Posca has very little smell, does not dissolve other inks as you write over them (which is useful for layering), and can be cleaned up with water while wet. Once dry, the paint is water-resistant on most surfaces. On glass or smooth plastic, it can be peeled off when dry unless sealed with a varnish.
Nib sizes explained
Posca makes markers in a range of nib sizes, each with a model number. The PC-1MR (0.7mm pin nib) is the finest and suits detailed illustration and fine writing on smooth surfaces. The PC-3M (1.0mm bullet nib) is a popular all-rounder for outlines, lettering and detail work. The PC-5M (1.8mm to 2.5mm bullet nib) is the most widely bought Posca size and the standard starting point for most sets. The PC-7M (4.5mm bullet nib) is used for bolder strokes and filling medium areas. The PC-17K (15mm chisel nib) is the largest standard Posca nib and is suited for signage, lettering and filling large areas.
If you are buying your first Posca set, the PC-5M in an 8-colour or 15-colour set is the most practical starting point. It is versatile enough for most projects without committing to a large set you may not use fully.
Surfaces Posca works on
Posca is tested to work on paper, cardboard, canvas, fabric, wood, stone, glass, ceramic, metal and most plastics. On paper and cardboard the paint dries permanently and will not lift with water. On fabric, the paint becomes wash-resistant after heat-setting with an iron. On glass and smooth plastic, the paint is removable with water while wet and becomes more durable once dry, but for permanent results on glass it needs to be sealed or kiln-baked. Stone and wood absorb the paint and hold it permanently without any additional treatment.
Tips for using Posca
Before using a new Posca marker, shake it well with the cap on, then depress the nib on a spare piece of paper several times to get the paint flowing to the tip. Do this with light presses rather than pressing hard once, which can damage the nib. Replace the cap when you are not writing to prevent the nib drying out. If the nib does dry, a damp cloth over the tip for a minute will usually revive it. Layering colours works well with Posca: apply the first colour, let it dry fully, then apply the second on top.