Wallis Sanded Pastel Paper Pad, Professional Grade, 12 in x 18 in, 8 SheetsA strong, non-buckling pastel paper ideal for under-painting in any medium, from watercolors to oil washes. Reworking is easy-simply remove pigment with a stiff brush. Two types are available. The Professional Grade uses a base paper of neutral pH cardstock. Both grades have identical surfaces and are coated with pH-neutral archival adhesive, a Wallis proprietary pH-neutral pigmented coating and inert white aluminum oxide grit. 8 sheets.