The invention relates to a method for producing flexographic printing forms by engraving a printing relief on a flexographic printing element that can be laser engraved, said element having a photochemically cross-linked relief layer. The relief layer is transparent and comprises oxidic, siliceous or zeolitic solid matter with a particle size between 1 and 400 nm in a quantity of between 0.1 and 8 wt. % in relation to the quantity of all components in the relief layer.