Since the base dyeing technique for mixed fiber is an application of that for each component, the focus is placed on single fiber dyeing techniques.

Table 3 shows fibers often found in mixtures, with examples of the dyes used and the optimum conditions for their single fiber dyeing.

Table 3 Fiber-dye combinations and optimum dyeing conditions

Table 3 indicates that one-bath dyeing is possible for mixtures whose fiber-dye combinations are under the same condition ranges of pH, dyeing temperature and so on.

It is also necessary to consider the possibility of two-bath dyeing not being suitable for mixed dyeing, with the risk of fiber deterioration depending on the condition of pH and temperature.

In mixed dyeing, dyes used for one fiber can easily cause staining on the other(s), often leading to troublesome color matching or fastness deterioration. Particularly in the dyeing of synthetic/natural fiber mixtures, the selection of dyes designed for mixed fibers is crucial as those used for synthetics have a tendency to cause considerable staining on the side of the natural fiber.

Uneven dyeing hardly becomes a matter in the dyeing of mixed fiber because unevenness does not particularly stand out visually, along with the fact that the fiber on the other side may promote a leveling effect, however, in the case of solid-shade dyeing, care is required in color matching with the conditions of the substrate such as the mixing ratio and state of the surface taken into consideration, as the balance between the shades and depths of both sides of the mixture can considerably influence the appearance of the mixture.

Selecting dyes with less staining effect on the other side, carrying out color matching based on the data of single fiber dyeing, and adjusting shades after being stained from the other side is a common method used in mixed fiber dyeing.

In the case of using dyes of the same group for both sides, such as in the dyeing of wool/nylon mixtures and cotton/linen or polyester/triacetate twisted union yarns, it is possible to select dyeing conditions for each dye in which both fibers are dyed in a solid shade (to the same depth), however, in combination dyeing, it is often difficult to find trichromatic colors that indicate the same dyeing behavior (or, that produce the same shades under the same conditions). As a practical color matching method, it is recommended to select dyes that bring about similar color tones, one darker than the target shade and the other lighter, to strike a balance between the two.