The natural color of most grades of lac gum that have not been bleached is some shade of orange, the depth of tone varying with the grade. The best grades of orange-shellac are not as apt to be adulterated with resin as the bleached. If more than a rather small per cent of rosin is present in shellac varnish, it will prevent the film from drying on a surface as hard as it should, leaving the finish tacky for a number of hours.

Orange shellac when dissolved in alcohol makes a better varnish than white shellac, because a film made with it is stronger and more elastic ideal for use on wood corner blocks, frieze boards, or bar rail moulding. In addition to these good qualities, the gum and prepared mixtures keep better. Alcoholic solutions of orange-shellac do not depreciate in quality through rather long periods of storage, and are far more stable than is the case with white-shellac solutions, which gradually deteriorate and become darker in color.

Orange shellac is objectionable for many purposes because of its color. Bleached or white shellac is made from the various orange or colored shellacs by several processes. The coloring matter consisting of red lac dye can be removed by the use of various weak alkaline solvents. Sometimes the orange-shellac resin is boiled in a weak solution of carbonate of potash, melted under water, and pulled till it is white. Another process is to dissolve the gum in some alkali and pass a stream of chlorine gas into the mixture to bleach the shellac, which is then melted under water and pulled when soft.

Treatment with hypochlorite of soda or potash, and then neutralizing with sulphuric acid, followed by filtering and washing in an elaborate process is a commercial method. Bleached shellac is sold on the market in a coarse granular or ground form in order to make it more soluble in alcohol. Sometimes it is obtainable in large hanks which keep to better advantage. The bleaching process reduces its solubility, leaves it in a condition so that it is very apt to deteriorate with age, and renders a spirit varnish made with it less elastic than that made from the untreated orange resin.

Bleached shellac dissolves in alcohol much more readily soon after it is manufactured. The gum gradually deteriorates with age or storage, and its solubility in alcohol is greatly reduced. White shellac varnish, when spread on a surface similar to designer window toppers or wood fireplace accessories, produces an effect of great brilliancy and unequalled transparency. It dries very hard, however, and on account of its lack of elasticity, it is apt to crack if it is bent or exposed to unusual conditions.

Shellac washes are wash coats of shellac, which are frequently used under paste filler in order to size the wood and keep the stain from raising with the filler when it is rubbed. Wash coats are made of thin shellac in the proportion of one part of standard liquid shellac to seven or eight parts of alcohol. Mixtures as thin as one to ten are usually satisfactory under paste filler. The proportion of one to seven is considered best when using a four-pound gum compound for the liquid-shellac portion.