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Watercolor First, Posca Lines After
- The method: loose watercolor washes first, let them dry completely, then do the line work with Posca paint markers.
- It works because Posca ink is opaque paint, not dye. It sits on top of the wash instead of sinking into it.
- The catch is that wet watercolor under a marker smears. Bone dry first, or it turns to mud.
- The paper is a compromise: heavy enough for water, smooth enough for the markers.
The usual order is lines first, then color inside them. It's easy to end up with something stiff that way, like a coloring book where someone was scared of going outside the edges.
So I'm trying it backwards. Watercolor washes first, loose and a little sloppy. Then line work over the top with PoscaA brand of paint marker filled with opaque, water-based paint instead of dye ink. A light color shows up over a dark one, and it's permanent on paper once it dries. markers once it's dry. The washes get to be as messy as they want, and the lines come in afterward to pull it together.
Why Posca works on top
Posca markers aren't really markers in the highlighter sense. They're water-based paint in a pen, pigment and all. That matters because paint is opaque. A light Posca line shows up over a dark wash, which a normal dye-based marker can't do.
It also means the line sits on top of the paper instead of soaking into it. On a watercolor wash, you get a crisp edge over a soft background, and that contrast is the whole look I'm after.
Once a Posca line is fully dry on paper, it's pretty much permanent. You can go back in with more water around it without the line bleeding.
The part that goes wrong
The wash has to be bone dry. Not "looks dry." Dry.
Watercolor stays re-wettable forever. That's one of its charms. If the paper is still damp, or if you scrub the marker back and forth, the marker tip picks up the paint underneath. The line goes muddy, and the marker tip gets stained with whatever color was under it. Now your white Posca is a sad beige Posca.
What I'm doing about it:
- Wait longer than feels necessary. A hair dryer on low speeds it up.
- One confident pass per line. Going over the same spot again is what lifts the paint.
- Test on a scrap of the same wash before hitting the real piece.
Tip
Some people spray a watercolor fixative over the finished wash before the markers go on. It seals the paint so the marker can't lift it. It's the fix if the mud keeps happening.
Paper, the annoying compromise
Watercolor wants thick, absorbent paper that won't buckle when it gets wet, usually 300gsm cold-pressTwo finishes of watercolor paper. Cold-press has a light tooth that holds washes well; hot-press is pressed smooth, which pens and markers prefer. with a bit of texture. Paint markers want smooth paper, because texture makes the line skip and the tip wear faster.
Those two wishes pull in opposite directions. The middle ground is heavier paper with a smoother surface, like hot-press watercolor paper or a good mixed-media sheet. Something that takes a wash without buckling and still gives the marker a clean run.
That's also what I'm looking for in a travel-size sketchbook: small enough to carry, heavy enough for water, smooth enough for Posca. If you've found one that nails all three, I'd genuinely like to hear about it.
Where this fits
This is a method I'm practicing, not a style I've arrived at. I keep a folder of references and tutorials for exactly this kind of thing, which I wrote up in Art and Drawing References.
And it has a job waiting for it. If the hardcover binding plan works out, those cases need cover art. Loose washes with bold lines on top would look right at home on an old library book.