noise texture generator

<svg xmlns="http://www.w3.org/2000/svg" width="0" height="0">
  <filter id="noise" x="0%" y="0%" width="100%" height="100%">
    <feTurbulence
      type="turbulence"
      baseFrequency="0.65"
      numOctaves="1"
      stitchTiles="stitch"
      result="noise"
    />
    <feColorMatrix
      type="saturate"
      values="0"
      in="noise"
      result="grayNoise"
    />
    <feBlend
      in="SourceGraphic"
      in2="grayNoise"
      mode="multiply"
      result="blended"
    />
    <feComposite in="blended" in2="SourceGraphic" operator="in" />
  </filter>
</svg>

/* CSS usage */
.element {
  filter: url(#noise);
  /* or as background overlay: */
  background-image: url("data:image/svg+xml,...");
  opacity: 0.60;
}