We don't have synonyms for ben day yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are benday and ben gay.
(n) :
(printing, attributive) A printing and photoengraving technique dating from the late 19th century, involving coloured dots or some other simple repeating pattern, spaced or overlapping, to produce more complex mixed colours.
(n) :
(printing, attributive) A printing and photoengraving technique dating from the late 19th century, involving coloured dots or some other simple repeating pattern, spaced or overlapping, to produce more complex mixed colours.