Miniature Paint Thinning Ratio Chart
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Every miniature painting technique wants a different paint consistency, and most painting problems, chalky basecoats, muddy washes, patchy glazes, trace back to getting that ratio wrong rather than to the paint or the brush. This chart gives starting ratios of paint to water or medium for each core technique, described by consistency since exact ratios vary by brand and pigment, so you can dial in the right thinness for whatever you are painting.
Basecoating: roughly 1 part paint to 1 part water
A basecoat wants full, even coverage in as few layers as possible, so the target consistency is close to whole milk: it should flow off the brush smoothly and self-level slightly on the model without beading up or running off in rivulets. Straight-from-the-pot acrylic paint is almost always too thick to basecoat cleanly and will show brushstrokes and an uneven, plasticky surface, so thinning roughly one part paint to one part water, adjusted by feel, is the standard starting point for most hobby-range acrylics.
Thicker, more opaque colors like white and yellow often need a slightly higher paint-to-water ratio to maintain coverage, while naturally staining or transparent colors thin further without losing much opacity. Two thin coats almost always look better and hide brush marks better than one thick coat, so err toward thinner rather than thicker when in doubt.
Washes and shades: roughly 1 part paint to 3 or 4 parts water or medium
A wash is built to flow into recesses and settle there while leaving raised areas comparatively clean, which requires a thin, watery consistency close to weak tea or skim milk, typically one part pigment to three or four parts water or a dedicated wash medium. Commercial pre-made washes like Citadel Shade paints or Army Painter Quickshade are formulated at this consistency already and used straight from the pot, while building a custom wash from a basecoat paint means thinning it down yourself to a similar thinness.
Adding a small amount of flow improver or a wetting agent, sometimes just a drop of dish soap in water-based paint, helps a thin wash flow into recesses evenly rather than beading up on the model's surface, which is a common frustration with very thin acrylic mixtures on a model that has not been primed evenly.
Glazing: heavily thinned, 10 to 20 percent paint
A glaze is an extremely thin, translucent layer of color, closer to tinted water than paint, used to shift the hue or add subtle color transitions over an already-painted area without covering what is underneath. A glaze medium, a clear acrylic base sold specifically for this purpose, holds pigment in suspension better than plain water at these extreme dilutions and prevents the paint from drying patchy or granular, so most experienced painters use a dedicated glaze medium rather than water once they move beyond simple washes.
Multiple thin glaze layers, allowed to dry fully between coats, build color gradually and predictably, while a single glaze mixed too strong behaves more like a wash and can pool or dry unevenly rather than laying down as a smooth veil of color.
Drybrushing: almost no thinning, wiped nearly dry
Drybrushing inverts the usual logic: instead of thinning the paint with liquid, you load a brush with paint close to its pot consistency, then wipe nearly all of it off on a paper towel or palette until the brush looks almost dry, leaving only enough pigment to catch raised edges and texture when dragged lightly across the model. Too much remaining paint on the brush deposits solid color rather than highlighting texture, which is the most common drybrushing mistake beginners make.
A stiff, slightly worn brush works better for drybrushing than a fine detail brush, since the stiffer bristles better catch and deposit paint only on raised surfaces, and many painters keep a dedicated set of older, splayed brushes specifically for this technique rather than risking their good detail brushes.
Airbrushing: roughly 1 part paint to 1 to 2 parts thinner
Airbrush-ready paint needs to be thin enough to atomize into a fine mist through a small nozzle without clogging, generally close to a skim-milk consistency, which for most hobby acrylics means somewhere between one part paint to one part thinner and one part paint to two parts thinner, adjusted for the specific paint line and nozzle size. Many manufacturers sell paint lines pre-thinned specifically for airbrush use, and dedicated airbrush thinner or flow improver generally outperforms plain water for consistency and reduces the tip-drying and clogging that water-thinned paint is prone to.
Nozzle size affects how forgiving the ratio needs to be: a 0.2 to 0.3mm fine nozzle wants thinner paint and is less tolerant of an overly thick mix, while a 0.4 to 0.5mm nozzle handles slightly thicker paint and larger pigment particles like metallics more reliably.