Purpose of a light table in graphic arts?

Purpose of a light table in graphic arts?
A light table is usually referred to as a table with a slightly transparent top with a light source underneath.This table is used to view photographic slides, photographic transparencies, film negatives and film positives to check color, quality and registration.You can also use it to trace other images onto paper or film.Before the advent of computers to set-up pages (layouts) for printing, light tables were used to layout typesetting and artwork onto "flats" prior to making negatives used to "burn" printing plates. The light tables allowed artists to see through the thin typesetting which was placed on the layout sheets that were prepared with faint blue lines to allow the type to be positioned easily.