Peta Hewitt has a tutorial video showing using them with the colored pencil underneath as a protective quality but I’ve found at least in Johanna Basford, Hanna Karlzon, Millie Marotta quality coloring books you can use them without any colored pencil underneath. Of course, always do a test...
Lost Ocean is the latest title by world-reknowned illustrator Johanna Basford, who spearheaded the adult coloring book movement with her earlier books Secret Garden and Enchanted Forest (see these two below in the Floral section). Get lost in an intricate underwater world blossoming with plant and...