Prussian Blue is Holbein's deep blue, built from PB29, PB15 Copper Phthalocyanine and PBk7 Carbon. Munsell reads 7PB 2.0/5.5, and that value of 2.0 is the number that matters: this is dark, close to the bottom of the scale, with a moderate chroma of 5.5. On paper it reads as a smoky near-black blue that only shows its hue where the light catches it or where you thin it out. Two stars for lightfastness.

Every palette wants one colour this dark that is not black, and this is it. It gives you night skies, deep water, cast shadow, ink-like line work and the bottom of a value range without the deadness that carbon black alone brings. Landscape painters use it to knock greens into shadow, and illustrators thin it for cool washes over dried flats. With Titanium White it climbs through a long ladder of cool greys, and against Burnt Sienna it makes a warm, controllable near-black. Model makers like it under metallics, where a dark ground earns its keep.

What Makes This Colour Special

Pigment, lightfastness and series as published by Holbein. Holbein does not publish an opacity rating for individual colours; the range as a whole is described by Holbein as opaque.

Acrylic Gouache, Not Traditional Gouache

Think of acrylic gouache as the flat-finish member of the acrylic family: a high pigment load, an acrylic emulsion binder, and a surface that dries without shine. Holbein Acrylic Gouache dries to a matte opaque finish and is water resistant once dry, so it does not reactivate with water like traditional gouache. With a very dark colour like Prussian Blue that matters more than usual, because a matte film reads as depth where a glossy one reads as reflection. If you already work in acrylic paint, the handling will feel familiar.

Standard acrylic dries with a sheen, and on a colour this dark a sheen is the enemy: every gloss patch becomes a highlight that fights your drawing. Acrylic gouache dries flat, so a deep blue like this reads as depth rather than as a shiny surface, and it photographs without hot spots.

Why Holbein Acrylic Gouache Is in Serious Studios

• Genuinely opaque. Holbein describes the range simply as an opaque acrylic paint. It covers, including over darker colour, which is the whole point of reaching for gouache rather than watercolour.
• Velvety matte, no sheen. Holbein describes the colour as opaque, intense, smooth and velvety. It dries flat, which is why it photographs and scans without glare.
• Water resistant once dry, so you can layer. Holbein’s own wording, and the reason the range exists. A dry layer will take another one over the top without lifting.
• The colour you mix is the colour you get. Holbein states it does not shift in colour tone from wet to dried colour. Anyone who has watched a perfect grey dry into a different grey will appreciate that.
• Built to use straight from the tube. Holbein says it is specifically designed to be used directly from the tube and will dry to even, uniform paint layers.
• Works on more than paper. Holbein lists paper, canvas, cloth, stone, wood, leather, plexiglass and concrete, with excellent adhesion, and full compatibility with all acrylic mediums.

Getting the Most Out of This Tube

Straight from the tube is the default. This is what Holbein designed it for, and it is where you get those even, flat, uniform layers. Add a little water to loosen it, but go easy: very diluted washes can dry streaky across a large flat area, so build coverage in thin even coats rather than flooding it on.

Watch the palette, not the clock. Holbein gives an open time of roughly 10 to 30 minutes and notes the drying time is much like ordinary watercolour. The practical consequence is that paint left sitting on the palette will go off and will not come back, so squeeze out small amounts as you need them.

It plays well with acrylic mediums. Holbein states the range is compatible with all acrylic mediums, so you can change the body or extend the working time if you want to. Soft synthetic brushes suit it, since they hold enough paint to lay a flat area without dragging.

Questions About Holbein Prussian Blue