Short answer: Don't paint straight from the pot. First, thin your paint with a little water or medium until it flows like skim milk, then build up two (or more) thin coats instead of laying down one thick one. This simple habit keeps detail crisp, prevents brush marks, and dries smooth. That's exactly why it sits under almost every technique you'll ever use.
In fact, "two thin coats" is the most-repeated rule in miniature painting. It first spread as Duncan Rhodes's signature mantra on Warhammer TV, and later became a paint range in its own right (Two Thin Coats, launched with Trans Atlantis Games on Kickstarter in 2021 and now over 180 colours). The rule itself is short: thin the paint and build it up in several thin layers rather than one heavy pass. This principle sits under basecoating, layering, glazing, edge highlighting — almost everything you'll do.
What is it and why does it matter?
At its core, two thin coats is the habit of getting paint to the right consistency and laying it down in several thin passes over the same surface. The goal is clear: to head off the three problems that pot-thick paint causes. Those three are filled detail, brush marks, and cracking.
A single thin coat has low coverage, so that first pass looks a little weak — but you make up for it with more coats. The result is colour that looks rich and a surface that stays glassy. And that's why the trade-off, thinner but more layers, wins every time.
Why do you need to thin paint at all?
Acrylic paint is deliberately made thick in the pot, both for shelf life and for coverage. That's precisely why, used straight from the pot on a miniature, it causes three kinds of trouble.
- It fills detail: Fine lettering, fur texture, and facial features vanish under the thick paint.
- It leaves brush marks: As it dries, you see ridges and streaks across the surface.
- It cracks and bubbles: Thick acrylic shrinks as it dries, which can lead to cracking.
A thin coat does the opposite: it settles into the surface, preserves detail, and dries smooth. Its only downside is reduced opacity — which, as we said, you simply solve with extra coats.
How do you judge the right consistency?
So how thin is thin enough? The target is usually described as somewhere between skim milk and whole milk. In other words, the colour should still look full, but it has to flow. Here the often-quoted yardstick from Tommie Soule of Brushstroke does the job.
According to Tommie Soule, your paint should be as thin as it can be without going transparent.
To catch this by eye, there are a few quick tests:
- Drag your brush across the palette. If the paint settles slowly into a flat, even surface, the consistency is right.
- If it pools in the recesses and leaves a "tide mark" at the edges, it's too watery — add a touch more paint.
- If it still drags like paste, it's too thick — add a few drops of water or medium.
How do you do it, step by step?
Two thin coats is really a habit, not a recipe, and over time you'll judge the consistency by eye. Still, starting from a clear sequence trains your hand and helps you catch mistakes early.
- Put a drop of paint on your palette. If you use a wet palette, it'll already sit at the right moisture.
- Pick up a drop of water or medium on the brush tip and mix it in. Start small, because under-thinning is far easier to fix than over-thinning.
- Mix and bring it to skim-milk consistency. Check it with the test above.
- Wipe the excess off the brush against the palette edge to balance the load, so the coat doesn't go on too thick.
- Lay down the first thin coat. The colour will look a little transparent — that's normal, so don't panic.
- Let it dry fully. Painting over a half-dry coat causes the layer underneath to lift.
- Lay down the second thin coat. Add a third or fourth on pale colours if you need to.
Which paints, brushes, and thinners?
Your choice of thinner depends on the job. They all dilute the paint, but they behave differently on the surface, with different finishes and drying times.
- Water: The simplest and most common option. Use distilled water, because the lime in tap water can leave marks.
- Acrylic / glaze medium (Lahmian Medium, Contrast Medium): It thins while protecting the pigment bond and opacity, and gives a satin finish. That makes it better than water for glazes and transparent transitions.
- Flow improver: It lowers surface tension and improves flow, which is great for airbrush work and fine lines.
- Retarder: It extends drying time, so it's essential for wet blending (mixing colours on the model while they're still wet).
On the brush side, a good synthetic or sable that holds a sharp point makes thin coats far easier. And keep one thing in mind: pale colours (yellow, white, light skin) are naturally less opaque, so thin them a little less and add more coats.
What are the most common mistakes?
Just about everyone who breaks the two-thin-coats rule falls into the same four traps. The good news is that each one has an easy, one-line fix.
- Not thinning at all: The classic beginner mistake. You get a thick, streaky, detail-drowning result.
- Over-thinning: Watery paint pools in the recesses and stays patchy and transparent — it ruins eyes and faces especially.
- Coating before it dries: The layer below lifts and bubbles. Here the only answer is patience.
- Always thinning the same ratio: Every brand and colour has a different consistency, so you have to adjust by eye; there's no fixed ratio.
Pro tips
There's no single answer to "how thin?" — it always changes with the job.
- Aim for slightly thin for basecoats, very thin for glazes, and medium-thick but still flowing for edge highlights.
- A wet palette is almost essential: it holds paint at the right consistency for hours and saves you from re-thinning constantly.
- Since pale colours are low-opacity, thin them less and lay down more coats.
- Don't fear a transparent-looking first coat; the colour builds as the layers stack up.
The patience rule: two thin coats always look better than one thick coat — no exceptions.
Frequently Asked Questions
What should I thin paint with, water or medium?
For simple basecoats and everyday work, distilled water is plenty. But when you want a glaze, a transparent transition, or a satin finish, a medium (Lahmian, Contrast Medium, glaze medium) is better, because it protects the pigment bond and opacity. You can also use both together.
How thin should the paint be?
Aim for a consistency between skim milk and whole milk. The colour should look full but flow freely. As a quick check: if you drag your brush on the palette and the paint settles slowly into a flat surface, it's right. If it's starting to go transparent, you've thinned too far.
How many coats should I apply?
Two thin coats saturate most colours. However, low-opacity colours like yellow, white, and light skin may need three or four. Don't count coats — judge the result: keep adding thin layers until the colour sits evenly and smoothly.
Do I really need a wet palette?
Not strictly, but it's almost essential for anyone working in thin coats. It holds paint at the right consistency for hours, stops it skinning over, and saves you re-thinning the same mix again and again. In short, it's a big payoff for a low cost.
Why does my paint crack or bubble?
There are two common causes: either you didn't thin the paint (thick acrylic shrinks and cracks as it dries), or you painted over a coat that hadn't fully dried. The fix is the same pair of habits: thin the paint, and let every coat dry completely before the next.
What happens if I over-thin?
Watery paint won't grip the surface; it runs into recesses and leaves a tide mark at the edges. The colour stays patchy and transparent, which wrecks small areas like eyes and faces. To recover, add a little more paint to the mix and rebuild the consistency.
Does this rule apply to every technique?
Yes, to nearly all of them. Basecoating, layering, glazing, edge highlighting, even washes rely on the right consistency. The thinning ratio changes with the job, but "never paint at pot consistency" is the shared foundation under every technique.
Key takeaway and next step
Remember one thing: thin the paint, then patiently build two thin coats. That single habit moves your work from amateur to clean craftsmanship. For your next step, look at the techniques most often paired with thin coats: Layering, Glazing, Edge Highlighting, Basecoating, and the tool that makes it all easier, Using a Wet Palette.
Hitting the right consistency comes down to a good brush, good paint, and a wet palette working together. If you want to round out your kit, browse our paints, brushes & hobby supplies.