It was not until 1940 he was able to present a woodcut with several grey tones, developed from the ordinary black printing ink.
en.wikipedia.org The traditional soft ground, requiring solvents for removal from the plate, is replaced with water-based relief printing ink.
en.wikipedia.org They sell to a wide range of industries like fireworks, paint, printing ink, mining explosives, ordnance, space, cutting tools, brake linings etc.
en.wikipedia.org The printing ink(s) must be chemically compatible with the lacquer used.
en.wikipedia.org It has a tackifying effect and is suitable for use in paint, printing ink, adhesives, rubber and other areas where tackiness is required.
en.wikipedia.org