b is the bottom image.
t is the top image.
normal(b,t)darken(b,t)multiply(b,t)color_burn(b,t)linear_burn(b,t)darker_color(b,t)lighten(b,t)screen(b,t)color_dodge(b,t)linear_dodge(b,t)lighter_color(b,t)overlay(b,t)soft_light(b,t)hard_light(b,t)vivid_light(b,t)linear_light(b,t)pin_light(b,t)hard_mix(b,t)difference(b,t)exclusion(b,t)subtract(b,t)divide(b,t)hue(b,t)saturation(b,t)