In the section “Prof. Theo de Beer about ….” we share with you articles from the unpublished book of Professor Theo de Beer “Everything about art materials”. Prof. Theo de Beer managed the Old Holland company from 1982 till 2000 and made a huge contribution to its development.
Ochre comes from the Greek word ‘Okhra’, which means earth colour. We have known ochre colours since antiquity. You can find the pigments, the natural iron oxides, in various different locations (mainly in Germany and Italy), so the same colour name from different manufacturers may show a variation in the colour tone.
There are different colours of ochre: yellow ochre, yellow ochre light, red ochre and brown ochre. Yellow ochre is P.Y.43, natural iron oxide. Red ochre is P.R.102, burnt iron oxide. Brown ochre is P.Br.7, a synthetic burnt natural red ochre, which is also an iron oxide.
All ochre pigments are lightfast. You can consider these as being semi-opaque pigments, which have a glazing effect. The opacity of the lighter ochre is slightly greater than the dark ochre, and they all form a strong layer of oil paint.
Ochre is highly suitable as a basis for muted hues. The tone of red ochre becomes more beautiful if you add a little light red to it. The synthetic iron oxide yellow (Mars yellow) is often used as a medium to imitate the yellow ochre colour. The colour of this Mars yellow looks similar to yellow ochre, but it has much more colour and opacity, and it does not have a glazing effect. Just as with the watercolours, it is easy to do the transparent techniques with the real yellow ochre. When used as a watercolour, the pigment particles of dark ochre in particular remain visible on the paper.