contrast()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2016.

The contrast() CSS function adjusts the contrast of the input image. Its result is a <filter-function>.

Syntax

css

contrast(amount)

Values

amount: The contrast of the result, specified as a <number> or a <percentage>. A value under 100% decreases the contrast, while a value over 100% increases it. A value of 0 or 0% will create an image that is completely gray, while a value of 1 or 100% leaves the input unchanged. Negative values are not allowed. The initial value for interpolation is 1.

The following are pairs of equivalent values:

css

contrast(0) /* Completely gray */
contrast(0%)

contrast(0.65) /* 65% contrast */
contrast(65%)

contrast(1)     /* No effect */
contrast(100%)

contrast(2)  /* Double contrast */
contrast(200%)

Formal syntax

<contrast()> = 
  contrast( [ <number> | <percentage> ]? )

Examples

With the backdrop-filter property

This example applies a contrast() filter via the backdrop-filter CSS property to the paragraph and monospaced text, color shifting to the area behind the <p> and <code>.

css

.container {
  background: url(image.jpg) no-repeat center / contain #339;
}
p {
  backdrop-filter: contrast(0.5);
}
code {
  backdrop-filter: contrast(0.15);
}

.container {
  padding: 3rem;
  width: 30rem;
}
p {
  padding: 0.5rem;
  color: #ffffff;
  font-family: sans-serif;
}

<div class="container" style="background-image: url(unity_for_the_people.jpg);">
  <p>
    Always ensure there is enough contrast between text and all background
    colors. If you think your text may land on top of a background image,
    include a <code>backdrop-filter</code>. Reducing the contrast of background
    colors with the <code>contrast()</code> filter may improve legibility but
    does not guarantee accessibility.
  </p>
</div>

With the filter property

This example applies a contrast() filter via the filter CSS property, changing contrast by shifting colors of the entire element, including content, border, background, and shadows.

css

p:first-of-type {
  filter: contrast(30%);
}
p:last-of-type {
  filter: contrast(300%);
}

p {
  text-shadow: 2px 2px blue;
  background-color: magenta;
  color: palegoldenrod;
  border: 1em solid rebeccapurple;
  box-shadow:
    inset -5px -5px red,
    5px 5px yellow;
  padding: 0.25rem;
  font-size: 1.25rem;
  font-family: sans-serif;
  width: 85vw;
}

<p>This paragraph has reduced contrast.</p>
<p>This paragraph has normal contrast.</p>
<p>This paragraph has increased contrast.</p>

With url() and the SVG contrast filter

The SVG <filter> element is used to define custom filter effects that can then be referenced by id. The <filter>'s <feComponentTransfer> primitive enables pixel-level color remapping. Given the following:

svg

  <filter id="contrast">
    <feComponentTransfer>
      <feFuncR type="linear" slope="2" intercept="-0.5"/>
      <feFuncG type="linear" slope="2" intercept="-0.5"/>
      <feFuncB type="linear" slope="2" intercept="-0.5"/>
    </feComponentTransfer>
  </filter>

.svgFilterLive {
  filter: url(#contrast2);
}

These values produce the same results:

css

filter: contrast(200%);
filter: url(#contrast); /* with embedded SVG */
filter: url(folder/fileName.svg#contrast); /* external svg filter definition */

This example shows three images: the image with a contrast() filter function applied, the image with an equivalent url() filter applied, and the original images for comparison:

<table cellpadding="5">
  <thead>
    <tr>
      <th><code>contrast()</code></th>
      <th><code>url()</code></th>
      <th>Original image</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>
        <img
          style="filter: contrast(200%)"
          src="https://mdn.github.io/shared-assets/images/examples/progress-pride-flag.jpg"
          alt="Pride flag" />
      </td>
      <td>
        <img
          class="svgFilterLive"
          src="https://mdn.github.io/shared-assets/images/examples/progress-pride-flag.jpg"
          alt="Pride flag" />
        <svg
          xmlns="http://www.w3.org/2000/svg"
          id="svg"
          viewBox="0 0 240 151"
          height="0"
          width="0"
          style="overflow: visible"
          color-interpolation-filters="sRGB">
          <filter id="contrast2">
            <feComponentTransfer>
              <feFuncR type="linear" slope="2" intercept="-0.5" />
              <feFuncG type="linear" slope="2" intercept="-0.5" />
              <feFuncB type="linear" slope="2" intercept="-0.5" />
            </feComponentTransfer>
          </filter>
        </svg>
      </td>
      <td>
        <img
          src="https://mdn.github.io/shared-assets/images/examples/progress-pride-flag.jpg"
          alt="Pride flag" />
      </td>
    </tr>
  </tbody>
</table>

Specifications

Specification
Filter Effects Module Level 1 # funcdef-filter-contrast

Browser compatibility

BCD tables only load in the browser