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 Cleanliness. Intentional staining is used in biochemical research, and for artistic effect, such as in wood staining, weathering steel and stained glass.
Types
There can be intentional stains (such as
or
paint),
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.
Numerous naturally occurring stains exist, such as
rust on iron and a
patina on
bronze,
as do accidental stains such as from
ketchup and
oil on
and other materials.
Different types of material can be stained by different substances, and stain resistance is an important characteristic in modern textile engineering.
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 action on the surface.
The material that is trapped coats the underlying material, and the stain reflects backlight according to its own color. Applied paint, spilled food, and
are of this nature.
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.
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.
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 products. Some products are designed to be applied directly onto stains. The removal of some types of stains requires chemicals or special techniques.
Some techniques for wood stain removal, involve first removing the protective layer (for example varnish) if there is one, before sanding and refinishing.
There are different techniques for removing rust stains, depending on the material this is on, for example clothing or concrete. Some housekeeping guides recommend using salt and lemon juice on clothing and specialist cleaners to remove rust from concrete, on areas such as driveways and patios.
See also
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 Marie Stain 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
External links
