Titanium dioxide undertone

When colour matching tinted compounds, it is usually necessary to use a titanium dioxide with the correct undertone - although compensation for small differences can sometimes be made by adjusting the tinting system. 

Titanium dioxide exists in two major crystal forms, rutile and anatase. Rutile is more closely packed and therefore denser than anatase. Compared with anatase, it has a higher refractive index and higher opacity. Because of its brilliant whiteness, excellent covering power, and resistance to color change, rutile is a valuable pigment for a broad range of applications in paints, plastics, inks, and paper. Anatase has a bluer undertone and is less abrasive than rutile. It is often preferred for applications in paper, ceramics, rubber, and fibers. 

Antimony oxide is also a brilliant white opacifying pigment with a pink undertone. However, it is much more expensive than titanium dioxide and finds httle use for this purpose. 

Phthalocyanine blues have excellent fastness and resisttuice properties. They are used in combination with titanium dioxide to produce durable strong or light blues. They are also used in blue metallic paints. Indanthrone blue, which has a red undertone is also used in automotive finishing. 

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