A concealer or colour corrector is a type of makeup used to mask pimples, dark circles and other small blemishes visible on the skin. Concealers usually do a good job of hiding blemishes by blending the imprefection into the surrounding skin tone. A concealer is mainly used by women, but use among men is increasing.

Both concealer and foundation are typically used to make skin appear more uniform in color. These two types of cosmetics differ in that concealers tend to be more heavily pigmented. Also, foundation is usually applied to larger areas than concealer is. The first commercially available concealer was Max Factor's erace, launched in 1938.

Concealer is available in a variety of shades, from lightest to deepest. Some colors are intended to look like a natural skin tone, while others are meant to contrast with a particular type of blemish. White can be used to blur dark circles or bruising, and to brighten dull skin. Green and blue can counteract red patches on the skin, such as those caused by pimples, broken veins, or rosacea.

A purple-tinted concealer can make shallow complexions look brighter. Colored concealers such as these are usually applied sparingly beneath a concealer or foundation that matches the wearer's skin tone. Skin-toned concealers are not only the most common type, but are often sufficient on their own at hiding/bluring imperfections.

Concealers come in a multitude of formulations, from moisturizing to acne-fighting. Concealers are produced from lightest coverage all the way to the heaviest coverage.

Let's use a scale system to show you the coverage level of a concealer (1-lightest to 7-heaviest). 1-loose powder concealer, 2-pressed powder concealer,3-matte mousse concealer, 4-pencil concealer, 5-liquid concelar, 6- Cream concealer, 7- Paste concealer. Depending on what type of imperfection you are trying to cover, will determine what form of concealer you will need. For example, hiding enlarged pores or mildly discolored spots may require a light concealer (1-3).

For hiding something like acne, dark circles, or eye bags, 3-6 would be ideal. But for hiding/blurring medical scars or moles you will need the heaviest product (6+).

Certain concealers may be used by itself, or in conjunction with foundation.