Titanium Dioxide: The Ultimate White Pigment for Artists and Paint Makers

Titanium white (titanium dioxide) pigment is a fine white powder. When used in paints, it provides for maximum whiteness and opacity. It gives paint high hiding power, meaning the ability to mask or hide the substrate underneath. It does this more effectively than any other white pigment. Today, titanium white pigment is the most important material used by the paint industry for whiteness and opacity. These unique properties are derived from the refractive index of titanium white. The refractive index expresses the ability to bend and scatter light. Titanium white has the highest refractive index of any material known to man, greater than diamond. To use this property, titanium white must be mined, refined, and ground to a fine, uniform particle size.

Titanium white pigments are developments of the 20th century, and because of their high hiding power, low toxicity, and reasonable cost, they have eclipsed other traditional white pigments.

Our titanium white is R2 grade rutile pigment that:

• Imparts maximum brightness and a neutral tone in white coatings,

• Produces brilliant, clean tints,

• It is readily dispersed and meets all requirements of modern production methods,

• It gives very high hiding power and is thus economical in use,

• Produces low-haze, high-gloss coatings, and

• It is suitable for all outdoor oil, solvent, and water-borne paints and coatings.

Origin and History

Titanium dioxide can refer to any pigment containing a compound of titanium. The name “Permanent White” has been applied to many pigments, including titanium white. Such imprecise names can confuse, and many are still used today. At the beginning of the 20th century, the development of titanium white pigment occurred simultaneously in Norway and the United States. Several processes were later developed and patented by companies in both countries. The use of titanium dioxide as a white pigment in artist’s palettes in field tests as early as 1916, but it wasn’t until twasn’t0s that widespread use of the pigment began.

Source

Nature does not yield titanium white in a form usable as a pigment. Titanium white is usually associated with iron, mainly as the mineral ilmenite. It is also mined in one of the pure forms, rutile beach sand. Deposits of titanium-bearing minerals used as the basic raw materials in manufacturing titanium white pigments can be found in many places on the earth.

Pigment manufacturers convert these raw materials to produce titanium white pigments. The production of titanium white pigments is a refinement process. This may be achieved by either the sulfate process, which uses sulfuric acid as a separating agent, or the chloride process, which works with chlorine. Once refined and developed to the appropriate particle size, the pigment may be surface treated with inorganic oxides and an organic compound to achieve better technical performance, such as easy processability or higher weather durability.

Permanence and Compatibility

Both rutile and anatase forms of titanium white are lightfast. However, according to Marilyn Laver (see note 6), exposure to light can cause a phototropic color change under certain circumstances. Rutile undergoes this reversible color change to a lesser extent than does anatase. The rutile and anatase pigment forms are chemically inert and do not react with airborne pollutants, organic solvents, or other pigments. Increased weather resistance and dispersibility of titanium white pigments are provided by coating the pigment with inorganic or organic substances. Our grade of titanium white is coated with alumina, silica, and zirconia compounds. Some suggest that the resistance of titanium white pigments to acids and alkalies is an advantage for their use in true fresco.

Oil Absorption and Grinding

Titanium white absorbs a low amount of oil. The oil absorption ratio is 15 to 20 parts by oil weight to 100 parts by weight of pigment. If the measurement were grams, it would require 15 to 20 grams (by weight) of linseed oil to grind 100 grams (by weight) of pigment to form a stiff paste. It makes an average to slow drying oil paint that forms a soft, brittle film.

Toxicity

Titanium white pigments have been produced and processed for nearly a century, and no acute or chronic harmful effects attributable to titanium dioxide have become known. Titanium white is not considered hazardous, but care should be taken when handling dry powder pigment to avoid inhaling the dust. The Occupational Exposure Standards (OES) for titanium dioxide in the air at the workplace have been set at 3 mg/m³ total respirable dust. Titanium white is not expected to have any mutagenic, carcinogenic, fibrogenic, toxic, or allergenic effects if this value is adhered to.

Rublev Colours Pigment: Titanium Dioxide (Titanium White)

Notes

1. The classification A1, A2, R1, R2, R3 corresponds to DIN EN ISO 591-1:2000, Part 1. The classification Type VII corresponds to ASTM D476 (2000).

2. The titanium dioxide content and density of the pigments depend on the type and quantity of the treatment substances used to improve the application properties. Pure rutile has a density of 4.2, while pure anatase has a density of 3.8.

3. Based on ISO 787/11.

4. The relative scattering power is the decisive parameter for titanium white pigments’ tinting strength and hiding power. The scattering power is determined based on DIN 53165.

5. Code for weather resistance:
A = Maximum weather resistance
B = Good weather resistance
C = Limited weather resistance

6. See Martin Laver, “Titanium Diox “de White” in Elizabeth” West Hugh, ed., Artist’s PigmeArtist’sandbook of Their History and Characteristics, Volume 3, Washington, D.C., National Gallery of Art, 1997), 340.