A heavy weight (55 lb.) natural tracing paper, Vidalon Tracing Vellum possesses a high transparency and an extra smooth finish. It.s also highly durable, resisting most scraping and repeated erasures.The vellum is perfect for line drawing with pencil, fibre tip pen, or technical pen. It.s suitable for microfilm offset and letterpress. Vidalon Tracing Vellum provides optimum storage properties and won.t yellow over time.Vellum sizes 23cm . x 30cm . and 36cm . x 43cm . come in tape bound pads of 50 sheets. Vellum sizes 50cm . x 60cm . and 60cm . x 90cm . is sold in individual sheets.