Although many of Zobel's works have survived, few of those by Haas have survived the passage of time, although observers considered his work superior to that of Zobel. This may reflect the differing techniques used by each artist. A diarist observed Zobel's coating the surface of the baseboard with a mixture of gum arabic and white lead and sprinkling sand upon the sticky surface using a folded paper funnel as a brush. He had to work quickly since the adhesive would dry in a few hours. Several of his surviving pictures have unfinished work on the reverse. Haas followed more closely the techniques developed in Japan, but mixing dry powdered gum arabic with the sand, sprinkling the mixture through a sieve and using feathers as brushes to create the pictures upon the baseboard, then fixing them by some method which he kept a secret. Due to the damp conditions in many of the stately homes of the day, his pictures failed to last more than a few years. On one occasion Haas was called away while working on an unfixed sand picture. When he returned he found one of Windsor Castle's cats curled up on the picture, thus damaging it!