XI 



PAINTS, DYES, AND VARNISHES 



ANY liquid substance that is applied to the 

 surface of a solid, either as a protective or for 

 decorative purposes, may be regarded as a 

 "paint," generally speaking. But when used in this 

 way the word is far too comprehensive. Subdivision 

 and classification of the substances used for coloring 

 is necessary for intelligent understanding of the subject. 

 Fortunately the substances all fall naturally into three 

 or four definite groups, determined either by their use or 

 by their chemical nature, although the dividing line is 

 not clearly drawn in some instances. 



For practical purposes the substances generally known 

 as pigments may be considered either as paints, var- 

 nishes, stains, or dyes. The last two are identical in 

 many instances, the substance upon which their appli- 

 cation is made, and the method of applying them, de- 

 termining whether they shall be called "stains" or 

 "dyes." Thus we speak of "staining" a piece of wood, 

 and of "dyeing" a cotton or wool fabric, although the 

 pigment used in each instance may be the same. 



Generally speaking, dyes, stains, and varnishes are 

 transparent or translucent substances in solution, or 

 chemical combination, with a liquid; while paints are 

 opaque, insoluble substances, held in suspension in 



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