Watercolour Investigations: Prussian Blue

Art Scribe Hand made watercolour Paints Prussian Blue paint box

Prussian Blue has an interesting story. From dyeing the Prussian army uniform to starring in many iconic works of art from Hokusais’ Great Wave to Picassos’ Blue Period. Let’s look at the watercolour characteristics of Prussian Blue. How it acts on the palette, its tonal range and the colours that can be mixed.

Prussian Blue has always been a much loved colour in my palette. Surprisingly to me, the reactions from some watercolour painters did not share this love. “Oh really!? It’s very staining”, “thats a hard colour to work with” and even; “I wouldn’t give it the time of day!”

Well we did give it the time of day, many hours in fact, as Reg set about mulling our first small batch of Prussian blue watercolour paint.

Hand mulling is a process that allows us to become more connected with the pigment and I became mesmerised as Reg moved the blue pigment across the glass slab in increasing circular movements. Like a black and magical mirror, the depth of the colour reflected back the room and ourselves, while streaks of brilliant electric blue shone through.

Experimenting with Prussian Blue:

Eagerly I set about exploring what our freshly made Prussian Blue could do on paper. My initial instinct was to work it with minimal dilution and use it over subtle yellows and bright greens to allow them to pop through the blue and give contrast. I threw salt crystals upon the wet surface in order for abstract stars to appear. I worked wet on wet, dropping Prussian Blue into pools of Hansa Yellow to watch it creep and blend organically. 

contrasting colours.
salt crystals.
wet on wet.

How Prussian Blue mixes, colour charts:

Once the expressive experimentation was out of my system, I explored some more deliberate and formal colour mixing. The results were beautifully subtle and delightfully surprising. 

Prussian & Burnt Umber: Teals, greys and earthy browns.
Prussian and Graphite Black: greys and blues for the shadows and stormy skies.
Prussian and Scarlet Deep: deep purples.
Prussian and Yellow Iron Oxide: earthy greens.
Prussian and Hansa Brilliant Yellow: vibrant greens.

Here’s how to read the colour charts above:

  • The two end columns are painted with unmixed, undiluted colour; i.e. Prussian Blue and Hansa Yellow.
  • The second column has the colours mixed: 2 parts Prussian to 1 part Hansa Yellow
  • The middle column has the two colours mixed in equal parts.
  • The forth column has the colours mixed: 1 part Prussian to 2 parts Hansa Yellow.
  • As you work down the chart, these mixes are gradually diluted thus creating the tonal range.

To Summerise:

Prussian Blue is staining in that it won’t lift off the paper completely. Instead it leaves a subtle water mark of itself. The other thing to be aware of is how it can quickly dominate a palette and colour mixes.

Used with care and mixed gradually, Prussian Blue will reward you with a diverse and exciting colour and tonal range. When mixed with yellows and greens, you have a vast range for painting foliage. Skies and seascapes become atmospheric with interesting granulation when mixed with Graphite Black or Burnt Umber. For the deepest darks and blacks you can’t go wrong with Prussian in the mix.

Prussian Blue will continue to be a favourite in my palette and I recommend exploring its qualities if you haven’t already. Finally, I invite the skeptics to give it another go and embrace its (magical) power! 

Browse our shop for Prussian Blue HERE.

Further reading about how Prussian Blue has been used in art history.