Gayle Mason, a friend of mine whose blog about her prize-winning rough collies and artwork is called "Fur in the Paint", has recently started to use drafting film for her coloured pencil artwork of animals and is greatly enamoured with it. You can use both the front and the back, mistakes in both coloured pencil and acrylic are easily erased and her work now takes much less time to achieve the same effect.
She's been posting recently about her experiment to find the best brand of coloured pencils to use on Polydraw, which is the brand of drafting film which Gayle uses. She's been creating a colour wheel chart to compare Prismacolors with Polychromos and so far Polychromos is proving to be the most successful. See the chart on her blog.
art , coloured pencils , colored pencils , drawing , rough collies ,