Va. Code Ann. § 17.1-239

All books used in the clerk's office for the permanent recordation of deeds, wills and other instruments shall either be made of high quality record paper, strictly number one rag stock, or permanent-durable, acid-free paper composed of strong, well-purified chemical wood fibers as prescribed by regulations pursuant to subdivision A 2 of § 42.1-82, or, if microfilm, microfiche, or microphotographic process is used in the clerk's office, the deeds, wills or other instruments shall be processed in accordance with standards established pursuant to § 42.1-82. All books are to be substantially bound, with a durable cloth or plastic cover over all.