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The CSS mask-type properties defines if a mask is used as a luminance or an alpha mask.

Initial valueluminance
Applies to<mask> elements
Computed valueas specified
Animation typediscrete
Canonical orderthe unique non-ambiguous order defined by the formal grammar


/* Keyword values */
mask-type: luminance;
mask-type: alpha;

/* Global values */
mask-type: inherit;
mask-type: initial;
mask-type: unset;


Is a keyword indicating that the associated mask image is a luminance mask, that is that its relative luminance values must be used when applying it.
Is a keyword indicating that the associated mask image is an alpha mask, that is that its alpha channel values must be used when applying it.

Formal syntax

luminance | alpha


Let's apply the following rectangle as a mask:

<rect x="10" y="10" width="80" height="80"
    fill="red" fill-opacity="0.7" />
which leads to the following square:

to this box:

The result, if your browser supports the property, with different value of mask-type applied to the <mask> element are these two different squares:

mask-type: alpha; mask-type: luminance;


Specification Status Comment
CSS Masking Module Level 1
The definition of 'mask-type' in that specification.
Candidate Recommendation Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (for SVG) 24.0 53.0 (53.0) No support 15.0 7
Applies to HTML elements No support 53.0 (53.0) No support No support ?
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support ? 53.0 (53.0) No support 15.0 No support

See also

  • Other mask-related properties: mask

Document Tags and Contributors

 Contributors to this page: chrisdavidmills, ntim, Sebastianz, fscholz, teoli, krit, kscarfone, Heycam
 Last updated by: chrisdavidmills,