ABSTRACT
Let’s examine this a little bit. Remember that this effect looks at neighboring pixels (within a 20-pixel radius, according to our Radius value). It then causes them all to be the maximum value in that search area (because of the Operation setting of Maximum). Because the value with the highest RGB values is white, the 20-pixel area all becomes white. If the stroke were black, then it
would have been completely replaced by blue, because blue has the greater of the RGB values.
