Fixative

Fixative is a term meaning "a stabilizing or preservative agent". There are several different compounds called fixatives:

Drawing
In drawing, a fixative is a liquid, similar to varnish, which is usually sprayed over a finished piece of artwork to better preserve it and prevent smudging. Artwork media requiring fixative include drawings done in pencil, charcoal, and pastel. An artist will often fix layers of a work in progress, in order to easily add further layers. Such a technique requires a workable fixative. Fixative is available in aerosol sprays.

Biology
In biology, a fixative is a solution used to preserve or harden fresh tissue or cell specimens for microscopic examination. Usually they stabilise and firm tissues by denaturing or cross-linking constituent proteins. Formaldehyde solution is an example of a fixative.

Perfumery
In perfumery, a fixative is a natural or synthetic substance used to reduce the evaporation rate and improve stability when added to more volatile components. This allows the final product to last longer while keeping its original fragrance. Fixatives are indispensable commodities to the perfume industry. Some examples of fixatives are sandalwood, musk, and orris root. Natural fixatives usually have a fragrance considered a base note, reflecting their low volatility.