This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
Incandescent light globes are colored by dipping the bulbs into a thin solution of collodion previously colored to suit with anilines soluble in collodion. Dip and rotate quickly, bulb down, till dry.
For office desks, room lights, and in churches, it appears often desirable to modify the glaring yellowish rays of the incandescent light. A slight collodion film of a delicate bluish, greenish, or pink shade will do that.
For advertising purposes the bulbs are often colored in two or more colors. It is also easy with a little practice to paint words or pictures, etc., on the bulbs with colored collodion with a brush.
Another use of colored collodion in pharmacy is to color the show globes on their inside, thus avoiding freezing and the additional weight of the now used colored liquids. Pour a quantity of colored collodion into the clean, dry globe, close the mouth and quickly let the collodion cover all parts of the inside. Remove the balance of the collodion at once, and keep it to color electric bulbs for your trade.