To use my knife technique I require highly viscous paints. Oil colors that are the consistency of jam are formulated to spread easily with a brush, but they either slide off the knife or form drooping strings that make precise control impossible. A thick and granular consistency is ideal for knife painting, but this consistency should not be achieved by the addition of fillers, which dull the colors. Dense pigments are more expensive but well worth it because they enhance viscosity without dulling the color. Several manufacturers make oil colors of a suitable consistency, but strangely no one manufacturer makes colors that are all free of what I call “stringiness”. Daler-Rowney Artists Oil Colours, Winsor and Newton and Old Holland are particularly suitable in consistency for knife painting, but there are odd exceptions. For example Old Holland earth colors are the perfect consistency for knife painting but their Titanium White is stringy. I use Daler-Rowney’s Titanium white.