Page:Violin Varnish and How to Make it.djvu/34

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HERE are two important qualities which the matter used in colouring must possess.

These are durability and solubility. The necessity of durability is obvious, and solubility is essential in order that the varnish may retain its full transparency.

Colouring matter that is not completely dissolved merely renders the varnish a mixture that has neither transparency nor beauty.

Many of the gums and rosins used give a certain amount of colour to its solvent, hence care must be taken not to add to a varnish a colour that does not naturally match with the original appearance, except in such cases where it is desired to obtain a special hue.