Work in Progress: David's Head in gouache

Beginning charcoal sketch of Michelangelo's statue of King David.  This is over phone book yellow pages adhered to Lanaquarelle 140 lb hot press paper, and is a work in progress.  Yesterday I had finished my watercolor study of David's head in preparation of this I'll do in gouache, using Turner paints.  The phone book pages are laid on top of a 1:1 ratio matte medium to water mixture brushed on, then strips of 1" wide masking tape on top of the pages, let set for 10 minutes and then remove tape and as much of the pages possible.  I let this one set about a minute too long as it did not all peel off.