darken / brighten is a general color effects plug-in whose features may sound a bit boring: It allows you to make parts of your clip darker or brighter. Still, the plug has some amazing capabilities that elevate it above most of the other one-trick pixel-pushers. It allows parallel darkening and brightening with relative and absolute values, allowing you to apply some special effects that would usually require multiple passes (and multiple plug-ins). The algorithm first applies the relative darkening or brightening, without applying any clipping to brightness. It then applies the absolute darkening/brightening, and only then clips the pixel's value to the legal range.