Posca pens: a complete guide to the world's most versatile paint marker
If you have not used Posca paint markers before, the most useful thing to know immediately is that they are not felt-tip pens. They look like felt-tip pens, they are held like felt-tip pens, and they come in the same kind of packaging — but what comes out of the nib is water-based acrylic paint, not ink. This distinction matters enormously for what they can do, where they can be used, and how they behave on different surfaces.
Posca is made by Uni, the Japanese marker and pencil manufacturer, and has been part of their range since the 1980s. It has become one of the most widely used artist tools in the world — used by illustrators, street artists, muralists, product customisers, sneaker painters, craft hobbyists, and schoolchildren, often for entirely different purposes with the same pen. The combination of opaque, vibrant, water-based paint in a marker format, available across a wide range of nib sizes and finishes, is genuinely difficult to replicate with any other single product.
We stock a comprehensive range of Posca pens at Craft and Canvas across multiple nib sizes, finishes, and price points. This post covers everything you need to know — what Posca actually is, the nib sizes and what each one does, the different finishes available, what surfaces they work on, how to use them, and which sizes to start with.
What Posca paint actually is
Posca markers contain water-based acrylic paint — a highly pigmented, opaque paint suspended in water and an acrylic polymer. This is the same basic chemistry as the tube acrylic paints used on canvas, but formulated to flow through a valve-and-nib system rather than being applied with a brush.
The practical consequences of this are significant. The paint is opaque — it covers what is beneath it, including dark surfaces, rather than being transparent like ink. It is lightfast and archival when dry. It is non-toxic and odour-free. It dries quickly to a matte finish. On porous surfaces like paper, card, wood, and unglazed ceramic, it bonds permanently. On non-porous surfaces like glass, smooth plastic, and glazed ceramic, it is water-resistant when dry but can be removed with an alcohol swab or solvent — which makes it ideal for surfaces where you want the option to correct or remove work.
The valve system inside each Posca marker means that shaking the pen mixes the paint before use and prevents the pigment from settling. Pressing the nib on a piece of scrap paper primes the tip and gets the paint flowing. Both steps are important — a Posca pen that has been sitting unused will need a good shake and a prime on scrap paper before it works properly.
What surfaces Posca works on
Posca's surface versatility is one of its most important qualities and the thing that makes it genuinely irreplaceable for certain applications.
Paper and card — Posca works on all paper and card surfaces. On smooth paper the mark is clean and precise; on textured paper there is a slight broken quality to the mark as the nib catches the texture. Particularly effective on black paper and dark card, where the opacity of the paint allows pale colours and white to read clearly.
Canvas — both primed and unprimed canvas accept Posca. On primed canvas the paint sits on the surface and produces clean, crisp marks; on unprimed canvas it soaks in slightly and produces a more matte, absorbed quality.
Wood — Posca adheres permanently to bare and painted wood and is one of the most popular materials for rock and wood painting projects. The paint bonds to the grain and produces vibrant, permanent colour once dry.
Stone and rock — rock painting is one of the most popular Posca applications at a craft level. The paint adheres to clean, dry stone and produces bright, permanent colour that is highly resistant to outdoor conditions. A coat of outdoor varnish significantly extends the longevity of Posca on stone for pieces that will be left outdoors.
Glass and glazed ceramic — Posca can be applied to glass and glazed surfaces. On these non-porous surfaces it is water-resistant when dry but not truly permanent — it can be removed with an alcohol swab. For permanent results on ceramic, baking the finished piece in a domestic oven at a low temperature heat-sets the paint and significantly improves durability.
Plastic — Posca adheres to most plastics and is popular for customising trainers, helmets, sports equipment, and other plastic items. A light sanding of the plastic surface before painting improves adhesion. On flexible plastics, a coat of flexible varnish prevents the dried paint from cracking.
Fabric — Posca can be used on fabric, though the result is not as permanent as specialist fabric paint. For best results on fabric, heat-set the dried paint with an iron through a pressing cloth. Wash inside out on a gentle cycle.
Metal — Posca adheres to clean, degreased metal and is popular for graffiti and street art applications, for customising metal objects, and for industrial decoration.
How to use Posca pens
Before use: shake the pen vigorously with the cap on for at least thirty seconds. The mixing ball inside the reservoir needs to move freely to mix the paint evenly before use.
Priming: remove the cap and press the nib firmly on a piece of scrap paper several times until paint flows into the tip. Do not press on your actual surface — this deposits too much paint at once and can flood the surface.
Applying: draw or paint directly onto the surface. Posca paint flows smoothly and evenly from a primed tip. For even coverage, work in one direction or in small circular motions rather than back and forth, which can lift wet paint.
Layering: allow each layer to dry completely before applying the next — usually a few minutes for a thin layer on paper, longer on non-porous surfaces. Once dry, a second colour applied over the first covers it completely. White or light colours over black paper or background produce clean, opaque results.
Blending: while the paint is still wet, two colours applied adjacent to each other can be blended at the edge using the tip of the pen or a damp brush. Once dry, blending is no longer possible but layering is.
Mixing custom colours: squeeze paint from different pens onto a ceramic palette, mix thoroughly, and apply with a brush. The paint behaves like standard acrylic paint when mixed in this way and can be applied with any acrylic painting technique.
Cleaning the tip: if the nib becomes clogged with dry paint or contaminated with another colour from blending, it can be removed, rinsed under water, and replaced. The paint inside the reservoir is not affected by rinsing the tip.
Storage: store Posca pens horizontally rather than vertically to keep the paint evenly distributed around the nib. Keep caps firmly on when not in use.
Which sizes to start with
For a complete beginner, two or three pens across different sizes give you access to most of what Posca can do. A PC-3M in black and white covers the majority of line work, detail, and correction applications. Adding a PC-5M in one or two colours gives you a medium filling tool. The PC-1MR or PC-1M is worth adding once you want to work at a finer scale.
For illustrators and artists, the PC-1MR or PC-1M for fine detail, the PC-3M for general drawing, and the PCF-350 brush tip for expressive mark-making is a strong professional working set.
For craft and decoration — rocks, wood, card making, ceramics — the PC-5M is the most versatile starting point, supplemented by the PC-3M for detail and the PC-8K for bold backgrounds and lettering.
For street art and large-scale work, the PC-7M, PC-8K, and PC-17K are the primary tools.
The nib sizes we stock
Understanding the Posca naming system removes most of the confusion about which pen to buy. PC stands for Posca, the number indicates the relative size of the nib (not a millimetre measurement), and the letter indicates the tip shape — M for bullet tip, K for chisel tip, F for brush tip, R for ultra-fine calibrated point.
PC-1MR — 0.7mm ultra-fine calibrated point — £4.99
The finest nib in the Posca range — a precision calibrated tip producing a consistent, hair-thin line of 0.7mm. The R designation indicates a rigid, precision tip rather than the compressible bullet tip of the other sizes. This is the pen for the finest detail work — intricate line drawing, precise outlines, miniature work, and any application where a consistent, extremely fine mark is needed. Its closest equivalent in feel is a technical drawing pen or a very fine fineliner, but with the opacity and coverage of acrylic paint.
PC-1M — fine bullet tip — £4.99
A fine bullet tip producing lines of approximately 0.7 to 1mm. Similar in scale to the PC-1MR but with the slightly more flexible bullet tip construction. Excellent for fine line work, detail, lettering at small scale, and precise decorative work. A very useful size for anyone who wants fine control without the rigidity of the calibrated point.
PC-3M — fine bullet tip — £4.99
A versatile fine bullet tip producing lines of 0.9 to 1.3mm — the most widely used Posca size for most drawing and illustration purposes. The PC-3M is the natural starting point for anyone new to Posca who wants to draw, outline, illustrate, or create detailed decorative work. It is fine enough for legible lettering and precise outline work, but substantial enough to fill small areas efficiently. If you buy one Posca pen to try the medium, the PC-3M is usually the right choice.
PC-3ML — glitter fine bullet tip — £4.99
The same fine bullet tip as the PC-3M but with glitter particles suspended in the paint, producing a sparkling, glittery mark. Particularly popular for card making, decorative work, and projects where a festive or celebratory character is wanted. The glitter finish makes this size more specialised than the standard PC-3M, but for the applications it suits it is particularly effective.
PC-5M — medium bullet tip — £5.49
A medium bullet tip producing lines of 1.8 to 2.5mm — the second most versatile all-round size in the range and the best choice for colouring, filling larger areas, and work that needs the boldness of a medium line without the heaviness of the larger sizes. The PC-5M is the standard choice for most colouring, lettering at medium scale, illustration with broader strokes, and surface decoration on rocks, wood, and other craft materials. Available in standard colours, fluorescent, and metallic finishes.
PC-5M Fluorescent — £5.49
The medium bullet tip in fluorescent colours — exceptionally bright, high-saturation yellows, pinks, oranges, and greens that produce maximum visual impact and glow under UV light. Fluorescent Posca is popular for signage, event art, posters, and any work where extreme vibrancy is the intention.
PC-5M Metallic — £5.49
The medium bullet tip in metallic finishes — gold, silver, copper, and other metallic colours that produce a convincing shimmer effect. Particularly effective on dark surfaces where the metallic quality reads most dramatically.
PC-7M — broad bullet tip — £6.99
A broad bullet tip producing lines of approximately 4.5 to 5.5mm. The PC-7M is the choice for covering larger areas, creating bold blocks of colour, background work, and lettering at a larger scale. It is also an excellent size for gestural, expressive mark-making where a more substantial line is wanted. Where the PC-3M and PC-5M are primarily drawing tools, the PC-7M starts to feel more like a painting tool.
PC-8K — broad chisel tip — £6.99
The chisel tip changes the character of the mark significantly. Where bullet tips produce a consistent line of a specific width regardless of angle, chisel tips produce a variable mark — turned one way they produce a fine edge, turned another they produce a broad stroke. The PC-8K has an 8mm chisel tip and is a favourite of street artists and muralists for its ability to produce both detailed marks and broad coverage with the same pen depending on orientation. Available in standard, fluorescent, and metallic finishes. Very effective for large-scale lettering and calligraphic mark-making.
PC-8K Fluorescent — £6.99
The broad chisel tip in fluorescent colours — high-impact for large-scale work, signage, and murals where visibility and vibrancy at scale are required.
PC-8K Metallic — £6.99
The broad chisel tip in metallic finishes — effective for large-scale decorative work, display lettering, and any application where metallic quality is needed across a broader mark.
PC-17K — extra broad chisel tip — £9.49
The largest chisel tip in our range — a 15mm broad chisel producing the widest, most substantial marks available in the Posca system. The PC-17K is for large-scale work: murals, signage, posters, background coverage, and expressive gestural mark-making at a scale where smaller pens would be too slow and laborious. It is not a precision tool — it is a coverage tool, and a very effective one.
PCF-350 — brush tip — £7.99
The brush tip Posca is the most versatile and most painterly of all the nib types. The flexible brush tip responds to pressure — light pressure produces a fine line, heavier pressure fans the tip to produce a broader stroke, exactly as a conventional brush does. This makes the PCF-350 the natural choice for anyone who wants the paint quality of Posca with the expressive, variable mark of a brush rather than the consistent line of a bullet or chisel tip. Excellent for illustration, watercolour-style painting, calligraphy, lettering with natural variation, and any application where a brush-like quality of mark is wanted.
Frequently asked questions about Posca pens
Are Posca pens permanent?
On porous surfaces — paper, card, wood, unglazed ceramic, stone, fabric — yes, once dry. On non-porous surfaces — glass, glazed ceramic, smooth plastic, metal — the dried paint is water-resistant but can be removed with an alcohol-based solvent. For permanent results on non-porous surfaces, apply a compatible varnish or sealant once the paint is fully dry.
Can I use Posca on dark paper?
Yes — one of Posca's great strengths. The paint is fully opaque and covers dark surfaces completely. White, pale, and bright colours on black paper or dark card appear at full intensity.
Can Posca pens be refilled?
No — the markers are not refillable. When the paint runs out the pen is finished. Buy individual replacement pens in the colours and sizes you use most.
What is the difference between bullet and chisel tips?
Bullet tips produce a consistent round line regardless of the angle of the pen. Chisel tips produce a variable mark — a fine edge or a broad stroke depending on orientation. Chisel tips are particularly effective for calligraphy-style lettering and for covering ground quickly at a large scale.
Can I mix Posca colours?
Yes — squeeze paint from the nib onto a palette, mix different colours, and apply with a brush or another pen. Two wet Posca marks adjacent to each other on the surface can also be blended at the edge while wet.
Do Posca pens work on watercolour paper?
Yes — the texture of cold press watercolour paper produces an attractive broken mark quality as the nib catches the raised texture of the surface. Hot press watercolour paper gives a smoother, more consistent mark.
Shop Posca at Craft and Canvas
We stock the full Posca range across all nib sizes — PC-1MR and PC-1M from £4.99, PC-3M and PC-3ML from £4.99, PC-5M standard, fluorescent and metallic from £5.49, PC-7M from £6.99, PC-8K standard, fluorescent and metallic from £6.99, PC-17K at £9.49, and PCF-350 brush tip at £7.99 — at Craft and Canvas in Hebden Bridge and online at craftandcanvas.co.uk.
Craft and Canvas | 3 Carlton Street, Hebden Bridge, HX7 8ER | craftandcanvas.co.uk