The ink flows smoothly onto plastic film and dries quickly. The red colored ink blocks a remarkable amount ultra violet light, as it is on the opposite end of the spectrum. The pen is recommended, for hand drawing, or touch ups on digital positive and negative film separations. While exposing ultra violet sensitive printmaking matrices, the printmaker will be rewarded with expanded window of exposure time and clean burns. Takach Press recommends this film opaquer pen when working with common photosensitive plates such as photolitho plates, and photopolymer plates.