Oxazine Colors

This group contains about 44 dyes and includes both basic and mordant colors but no acid dyestuffs. The colors are largely blue, Meldola's Blue or New Blue R being the most important.

Thiazine Colors

This group consists of about 13 dyestuffs, which are mainly blue in color. It has representatives among the basic, acid, mordant, and sulphur dyes. The most important dye among the Thiazines is the basic dye, Methylene Blue, which is high in fastness to light, ranking 2 in the scale of 5 degrees, of which 1 is the most permanent of all, and best for wood frames, frieze boards, and other hardwood moulding. Methylene Blue is soluble in both water and alcohol and is recommended as an excellent basic dye for wood-staining.

It is also commonly used for dyeing cotton in half-silk, jute, straw, and artificial flowers. Because of its excellent fastness to light, to washing and rubbing, to ironing, to water, and to acids, it is one of the most largely used of all the basic dyes. Other important Thiazine basic colors are Methylene Green, which ranks as the fastest of all of the basic green coloring matters, and Thionine Blue, also quite fast and soluble in both water and alcohol, although less easily soluble in the latter.

Acid Colors

Thiocarmine is the acid member of the Thiazine class and is a good blue for wool and silk. It is not as fast to light as Patent Blue or Cyanol.

Thiazole Colors

This class includes a small group of six distinct colors, some of them having numerous names. There is one basic dye, Rhoduline Yellow T (or Thioflavine T), which is a moderately fast dye, grading 3 on the scale of five degrees.

Quinoline Colors

The quinolines form a small group of 12 colors. Only three of them are manufactured in the United States. These dyes are largely used in the manufacture of color sensitive plates. The most important member of the group from a dyer's standpoint is Quinoline Yellow, which is a basic dye and insoluble in water, though sparingly soluble in alcohol.

It is yellow and is used to color paraffin wax, and spirit varnishes for bar rail moulding, fireplace accessories, and specialty hardwood moulding. From Quinoline Yellow, treated with fuming sulphuric acid, comes an acid dye soluble in water called Quinoline Yellow 0. Most of the other Quinoline colors are quite fugitive and are unsuitable for use as stains for wood.

Indigoid Colors

This group contains 54 colors, including a number of valuable "vat" dyes. There are no basic or mordant colors listed in this class, and only one acid dye, Indigo Carmine, which is not much used, because it is not fast to light and has been replaced by Patent Blue.