Stain

For stains in woodworking, see wood stain. For the scientific and medical technique, see Staining. For other uses, see Stain (disambiguation).

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

Coffee stains

Types

There can be intentional stains (such as wood stains or paint),^[1] indicative stains (such as food coloring dye, and staining, the use of one or more substances to enhance visibility of samples in a microscope or other imaging device.^[2] Numerous naturally-occurring stains exist, such as rust on iron and a patina on bronze,^[3] as do accidental stains such as from ketchup and oil on fabrics and other materials.

Different types of material can be stained by different substances, and stain resistance is an important characteristic in modern textile engineering.^{[citation needed]}

Stained waistcoat, originally that of a Royal Navy captain of the Victorian era

From a copy of "Decorative Patterns of the Ancient world," by Sir Flinders Petrie.^[4]

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.^[1] The material that is trapped coats the underlying material, and the stain reflects backlight according to its own color. Applied paint, spilled food, and wood stains are of this nature.^[5]

A secondary method of stain involves a chemical or molecular reaction between the material and the staining material. Many types of natural stains fall into this category.^{[citation needed]}

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.^[6]

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 removal is frequently a highly desired characteristic in laundry detergents and other types of cleaning agent. Some agents are designed to be applied directly onto stains. The removal of some types of stains requires other chemicals or special techniques. Use of an inappropriate technique could make permanent an otherwise removable stain or cause unwanted discoloration of clothing.^[7]

See also

• Biodegradation
• Bleach
• Dye
• Foxing
• Permanent marker
• Weathering steel

References

1. Bob Flexner (1999). "Understanding Wood Finishing: How to Select and Apply the Right Finish". Reader's Digest: 121. ISBN 978-0-7621-0191-7.
2. George Clark, James W. Bartholomew (1981). Staining Procedures Used by the Biological Stain Commission: Published for the Biological Stain Commission. Williams & Wilkins. pp. 32–33. ISBN 978-0-683-01707-6.
3. L. William Zahner (1997). Architectural Metals: A Guide to Selection, Specification, and Performance. Wiley. p. 101. ISBN 978-0-471-04506-9.
4. "Decorative patterns of the Ancient World : Flinders, Petrie : Free Download, Borrow, and Streaming : Internet Archive". Internet Archive. 2023-03-25. Retrieved 2024-02-17.
5. NACE International (1987). Materials Performance. Vol. 26. National Association of Corrosion Engineers. p. 33.
6. Max Alth, Simon Alth (1977). The Stain Removal Handbook. Hawthorn Books. p. 22. ISBN 978-0-8015-7071-1.
7. Solutions for Clothing and Laundry Stain Removal

Further reading

• Stain & Spot Removal Handbook: Consumer guide. by the editors of Consumer Guide. Skokie, Ill: Beekman House, 1981. 9780517316832
• Zia, Stephanie. Stain Removal. London: Hamlyn, 2005. Distributed in the U.S. and Canada by Sterling Pub. Co., 2005. 9780600611240
• Soto, Anne MarieStain Rescue!: The A-Z Guide to Removing Smudges, Spots & Other Spills By good Housekeeping Institute (New York, N.Y.). Published by Sterling Publishing Company, 2007 ISBN
• Mendelson, Cheryl Laundry: The Home Comforts Book of Caring for Clothes and Linens Simon & Schuster, 2005 ISBN 978-0-7432-7145-5

External links

• Stain removal guide, American Cleaning Institute
• The dictionary definition of stain at Wiktionary
• Media related to Stain at Wikimedia Commons