A painting medium it will not mix such as oil and water, or water and resin, unless combined by the addition of an emulsifying agent. Emulsifying agents can be 'natural' such as egg-yolk, albumen and lecithin. Source: Ralph Mayer, "A Dictionary of Art Terms and Techniques" <br><br>A liquid in which small droplets of one liquid are immiscible in, but thoroughly and evenly dispersed throughout, a second liquid. eg. Acrylic Emulsion<br><br>Casting of light-sensitive chemicals on papers, films, printing plates and stencils.<br><br>A suspension of small globules of one liquid in a second liquid with which the first will not mix. A photosensitive (light sensitive) material which consists of a coating of silver halide grains in a gelatin layer, on photographic metal plates (for a daguerreotype), glass plates, film, fabric, paper, or other surfaces.(pr. ə-MUL-shən)Also see emulsifier, negative, photography, positive, and stain.