Saying Goodbye is Never Easy...
Denril Multi-Media Polypropylene Film was discontinued in 2021 due to permanent supply chain issues brought forth by the Covid-19 pandemic. It has been a favorite product within the Borden & Riley family of papers, and has offered artists a multitude of uses over its lifetime. While we do not have a one-for-one replacement for Denril, we can suggest a few options across Chartpak's brands that may meet your artistic needs.
Clearprint has a wide variety of transparent vellum papers. The heavy vellum sheet handles markers and some fluid media like gouache and acrylic. The 1000H Series of Clearprint is a lighter sheet made from 100% cotton, making it very strong. Many types of dry and fluid media are compatible with Clearprint. Because this is a paper and not a film, the open time for fluid media is shorter on Vellum than Denril.
Similar in Transparency to Denril, Boris Marker Paper is great for use with all types of markers. Guides can be seen through the sheet making it a useful paper for hand lettering and calligraphy. Resists feathering and bleeding while keeping lines crisp and colors vibrant. Boris is not great for heavy applications of fluid media.