The key to successful appearance when using pigments is to apply small quantities at a time. This approach allows the gradual build-up of colour and texture, so that the subject is not overwhelmed. My technique involves the following steps:

• Make sure that the lid of the container is properly screwed on
• Give the container a brief shake
• Tap the container firmly on the work surface
• Open the container and inspect the inside of the lid/cap, where you should see a thin film of pigment
• Pick up some of this thin film on the tip of your filbert brush
• Tap the brush on the edge of the lid or pot
• Gently apply the remaining pigment to the model, moving the brush in a downward motion in the manner that rain would carry the dirt.

The process will allow the representation of a dirt build-up that occurs over time: