You’ve got your sketch in front of you.
The watercolour is down — pools of pigment settling into paper – and you’re hovering, wondering…
Do I leave it as it is, or is it time for the brush pens?
This moment – the pause between stages – is where a lot of sketchers feel uncertain. Knowing whether to let watercolour carry the tone or to step in with your Tombows can make the difference between a lively, balanced piece and one that feels overworked.
Here’s how to decide.
Step One: Let Watercolour Set the Stage
Watercolour is your big-picture tonal tool.
This is where you decide where the light falls, which areas are in shadow, and how the overall mood feels.
- For drama and depth: Use richer pigment and less water.
A mix of Prussian Blue and Transparent Orange creates a deep, complex tone perfect for archways, shadowed windows, or the underside of a bridge. - For softness and light: Add more water.
This opens up the tone, making skies and open spaces feel airy and energetic. - For interesting neutrals: Mix on the page.
Ultramarine with Burnt Sienna gives a warm grey; Cobalt Turquoise with Transparent Orange makes a more earthy tone.
At this stage, you’re not “finishing” anything.
You’re laying an underpainting – a loose foundation that leaves room for the next layer to do its work.
Step Two: Use Brush Pens for Control and Clarity
Once your wash is dry (or nearly dry), brush pens come into their own.
They don’t compete with the paint — they work with it.
- Add depth where needed
If a shadow feels too soft, a mid-grey Tombow like N60 or N79 can strengthen it without muddying the colour. - Blend and soften
Tombows are water-soluble. With a damp brush, you can smudge a harsh edge or blend tone into surrounding colour. - Fine-tune problem areas
Got a paint bloom that feels distracting? A light grey (N89 or N95) can gently calm it without covering your wash completely.
Think of brush pens as your precision tonal tool — they’re there to bring structure, settle the chaos, and shape the scene.
Which Comes First? The Layering Mindset
Here’s the simplest way to think about it:
- Watercolour = energy and atmosphere
- Brush pens = definition and focus
Tone builds best in layers. Start loose and expressive with paint. Let it breathe. Then, once you can see what the picture is asking for, bring in the brush pens to guide the eye and strengthen the form.
Four Quick Tone Tips for Your Next Sketch
- Tone matters more than colour – light, mid, and dark values are the backbone of your composition.
- Don’t overpaint – leave room for later adjustments.
- Mix on the paper – it keeps your tones lively and unpredictable.
- Ask what the sketch needs – more mood? That’s paint. More structure? That’s pen.
Want to go deeper?
In our Urban Sketch PLUS membership, you’ll find dedicated lessons on tonal work – from layering greys and controlling contrast to blending brush pen and watercolour seamlessly. You’ll build the confidence to decide, instinctively, which tool to reach for next.
