Vegetable Tanned Leather Notebooks Covers. Vegetable tanning was the major tanning method until the 20th century and is now growing in importance once again. It uses extracts of barks, leaves, fruits, berries, roots and wood. This method of tanning is safe for the environment and leather workers. Vegetable tanned leather is left to breathe, It can take up to 2 weeks to dry until they turn a beautiful beige colour. Nature’s elements seep into its grain over time, enhancing its authentic and earthy character, These notebooks will age beautifully over time. These are good sized notebooks with strap. With unlined pages, so you can write or sketch.