Like offset litho, gravure can be printed onto a web. The process is digitally prepared : diamond styli in the engraving heads that cut the printing cells are driven from digital files. An engraved cylinder revolves in a reservoir of thin, solvent-based ink, flooding the surface. A flexible steel ‘doctor blade’ wipes the cylinder clean as it revolves, leaving ink only in the image areas. Finally, a rubber-covered impression cylinder presses the paper onto the engraved surface. One drawback of gravure is that type appears less sharply than with lithography.