A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Accidental staining may make

materials Material is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geolog ...

appear used, degraded or permanently unclean. Intentional staining is used in biochemical research and for artistic effect, such as

wood staining Wood stain is a type of paint used to colour wood and consists of colourants dissolved and/or suspended in a 'vehicle' or solvent. Vehicle is the preferred term, as the contents of a stain may not be truly dissolved in the vehicle, but rather ...

, rust staining and stained glass.

Types

There can be intentional stains (such as

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...

stains or paint), indicative stains (such as

food coloring Food coloring, or color additive, is any dye, pigment, or substance that imparts color when it is added to food or drink. They come in many forms consisting of liquids, powders, gels, and pastes. Food coloring is used in both commercial food ...

or adding a substance to make bacteria visible under a microscope), natural stains (such as rust on iron or a patina on bronze), and accidental stains such as ketchup and synthetic oil on clothing. Different types of material can be stained by different substances, and stain resistance is an important characteristic in modern textile engineering. Waistcoat, naval (AM 2015

Formation

The primary method of stain formation is surface stains, where the staining substance is spilled out onto the surface or material and is trapped in the fibers, pores, indentations, or other capillary structures on the surface. The material that is trapped coats the underlying material, and the stain reflects back light according to its own color. Applying paint, spilled food, and wood stains are of this nature. A secondary method of stain involves a chemical reaction, chemical or molecular reaction between the material and the staining material. Many types of natural stains fall into this category. Finally, there can also be molecular attraction between the material and the staining material, involving being held in a covalent bond and showing the color of the bound substance.

Properties

In many cases, stains are affected by heat and may become reactive enough to bond with the underlying material. Applied heat, such as from ironing, dry cleaning or sunlight, can cause a chemical reaction on an otherwise removable stain, turning it into a chemical.

Removal

Various laundry techniques exist to attempt to remove or reduce existing stains. Stain remover is an important type of chemical in laundry detergents and some removers are formulated to be applied directly onto stains. The removal of some stains require other chemicals or special techniques. Use of an inappropriate technique could make permanent an otherwise removable stain or cause unwanted discolouration of the clothing.Solutions for Clothing and Laundry Stain Removal
/ref> Information about stain removal can be found in magazine, magazines, book, books, advertising, advertisements or World Wide Web, online:
Stain removal guide
American Cleaning Institute
Stain solutions
University of Illinois * Stain removal advice from Procter & Gamble
UKCanada

References

External links

* * {{Laundry navbox Laundry Artistic techniques