I have recently gotten into scanography, but I have not yet found a good method to protect the scanner glass from objects that will scratch or soil it. I need to find a material that is optically neutral and thin.
I have tried acetate sheets (sold as document protectors), but they are only optically neutral for perfectly flat items, such as documents. I got some clear plastic document protectors, but they crinkle and have undesirable reflective properties. I could use glass (I do have a broken scanner lying around), but unless the glass is incredibly thin, it will cut into my depth of field, which is important to me.
So what is the optimal material? It needs to be optically neutral, low-reflective, not prone to wrinkling, as thin as possible, and preferably cheap and/or reusable.