Full grain is a type of leather whose natural grain markings have not been corrected or altered in any way. It often displays natural characteristics and subtle markings that occurred during the life of an animal like insect bites, scars, and scratches. Full grain leather will develop a patina as it ages over time.
Yates, Marypaul, and Adrienne Concra. Textiles for Residential and Commercial Interiors. 2019.