contrast()

Defines the contrast on an element.

filter: contrast(<value>);

where a required <value> can be one of the following:

• Number value: 0, 1.4
• Percentage value: 100%, 50%

Note: Values of 1 and 100% will have no effect. Values greater than 1 and 100% will increase the contrast. Values less than 1 and 100% will decrease the contrast. A value of 0 and 0% will be completely gray.

Give the image a contrast of 200%:

.banner-image {
  filter: contrast(200%);
}