Type: string ("normal", "darken", "multiply", "color-burn", "lighten", "screen", "color-dodge", "overlay", "soft-light", "hard-light", "difference", "exclusion", "hue", "saturation", "color", "luminosity", "source-in", "source-out", "source-atop", "destination-over", "destination-in", "destination-out", "destination-atop", "dissolve", "linear-burn", "linear-dodge", "darker-color", "lighter-color", "vivid-light", "linear-light", "pin-light", "hard-mix", "subtract" or "divide")