Very complicated processes are currently necessary for the production of needle-shaped magnetic pigment particles. As regards needle-shaped pigments, chromium dioxide with a rutile structure is favored. It tends to crystallize as needles under hydrothermal production conditions (decomposition of CrO₃ in an oxygen atmosphere or reaction of CrOOH with CrO₃).

The manufacture of iron oxide-based needle-shaped magnetic pigments is much more complicated as γ-Fe₂O₃, Fe₃O₄ and metallic iron (all cubic) do not crystallize in a needle-shape. It is therefore necessary to start from needle-shaped precursors. Nonmagnetic α-FeOOH (goethite) or γ-FeOOH (lepidokrokite) produced by precipitation and oxidation from Fe(Ⅱ)-salt solutions are suitable precursors which can be converted into ferrimagnetic magnetite by dehydration and reduction and into ferromagnetic metallic iron by complete reduction.

In the synthesis of γ-Fe₂O₃, careful oxidation of magnetite in a spinel lattice to a superstructure of crystallizing ferrimagnetic γ-Fe₂O₃ (maghemite) under well-defined conditions is necessary:

Since the starting material is chemically and structurally changed several times, it is important that the initial needle shape be retained as completely as possible during the synthesis by, for example, using protective layers.

Recently ever more use has been made of the coercivity-increasing effect of cobalt in the magnetic iron oxides. The cobalt is either incorporated homogeneously into the iron oxide lattice (bulk doping) or the needles of the finished γ-Fe₂O₃ or Fe₃O₄ magnetic pigment are epitaxially coated with a layer of cobalt ferrite. Coercive forces of 380 to 750 Oe require ca. 1 to 4% Co. Such products have comparable properties to CrO₂-pigments.

The world production capacity for magnetic pigments in 1991 was ca. 40^.10³ t, magnetic iron oxide pigments accounting for over 90% of this. Metallic iron pigments are preferred for 8 mm camcorders tapes.

It is mainly utilized in the manufacture of video tapes (VHS) Metal pigments are increasingly being used in 8 mm video formats and R-DAT.

The importance of audio cassettes has waned, since the introduction of the compact disc.