WHICH WHITE IS WHICH
Some would say that the most important colour choice artists make is the white they choose to include in their palette. So here is some information which will help you sort your whites from your whites.
There are basically three types of white pigment used in the manufacture of white oil paints. Their tinting properties and the type of oil used as a binder will determine the nature of the paint produced.
1. Lead Oxide (PW1).
For the first few hundred years this was the only white pigment available to artists. Known as Flake White or in some cases ‘Cremnitz White’, it is a fast drying paint favoured by artists because of its high tinting quality and for being completely opaque.
Being made from lead, it is hazardous and in powder form lead oxide is very poisonous as it is easily inhaled. Lead is an accumulative poison which damages brain cells and affects the nervous system.
By the 19th Century alternate white pigments had been discovered and in the 20th Century the use of lead oxide in artists paints had been discouraged and was banned in many countries.
Lead is still a favoured pigment particularly for priming canvasses. It is prized for its warmish tone and high covering power.
2. Titanium oxide (PW6).
Today, the most widely used white pigment in paints and inks and can also be found in food and cosmetic products. In the manufacture of artists’ oil paints it is the main ingredient in Titanium White.
It became a popular alternative to flake white during the 19th Century as it produces an opaque white paint which is slow drying.
3. Zinc Oxide (PW4).
A transparent white pigment which has little tinting power. Artists find it good for creating glazes and scumbling where it is used to modify a layer of colour. Because of its ‘poor’ covering power it will not hide the layer of paint below it.
Think of the transparency of a woman’s veil in a painting, or mist and haze in a landscape.
The type of oil used to bind the pigment powder is important as it will influence the colour of the white paint produced. Linseed oil will give the white a warm tone as it is a ‘yellow’ oil, whereas safflower oil is whiter and so produced a cooler white paint. Upon ageing, whites produced with safflower oil tend to hold their colour the best.
Modern paint choices.
Manufacturers use these pigments in pure or mixed form to produce white paints with varying characteristics.
Titanium is not known for its ‘brushability’, whereas Zinc offers better handling properties, so a little Zinc Oxide is added to Titanium white making it easier to work with the brush.
Lead Oxide is a fast drying pigment so it is sometimes added to other white pigments to speed up drying times. Most reputable manufacturers will list the ingredients on their labels which will help you make your choices. Whichever white you choose, it is always best to use the ‘artists’ quality because in the students paint you will find that varying amounts of ‘fillers’ such as chalk are used, and the amount of actual white pigment is minimal.
