Information about base material can be very useful for identification and selection, e.g., parchment, or plastic as the base material for a book, instead of print
Check the 'Source' instruction to be sure that you are looking at the correct source(s) of information on the resource
If data on the resource and data as the element in the record are:
data for this element must be Recorded from a vocabulary (Open): the term(s) must be appropriate for the resource, even if they are not from the official list of terms
but be sure to check the resource carefully, if the data for the element is Core, or if the data is important for differentiating the resource from a similar resource