public function apply($image)
{
// normalize colorize levels
$red = $this->normalizeLevel($this->red);
$green = $this->normalizeLevel($this->green);
$blue = $this->normalizeLevel($this->blue);
$qrange = $image->getCore()->getQuantumRange();
$image->getCore()->levelImage(0, $red, $qrange['quantumRangeLong'], \Imagick::CHANNEL_RED);
$image->getCore()->levelImage(0, $green, $qrange['quantumRangeLong'], \Imagick::CHANNEL_GREEN);
$image->getCore()->levelImage(0, $blue, $qrange['quantumRangeLong'], \Imagick::CHANNEL_BLUE);
return $image;
}