▁the ▁advent ▁of ▁phot ol ith ography , ▁plans ▁( which ▁may ▁have ▁measured ▁ ▁were ▁reprodu ced ▁pain st aking ly ▁by ▁dra ug ht s men ▁to ▁ 1 / 2 ▁or ▁ 1 / 3 ▁scale ▁onto ▁prepared ▁stone ▁sl abs , ▁a ▁process ▁which ▁could ▁take ▁days ▁or ▁weeks . ▁In ▁most ▁cases ▁the ▁exp ense ▁in ▁prepar ing ▁a ▁copy ▁was ▁so ▁great ▁that ▁the ▁stone , ▁which ▁could ▁we igh ▁ ▁was ▁stored ▁against ▁the ▁need ▁for ▁future ▁re - use . ▁The ▁cost ▁and ▁log istics ▁of ▁conser ving , ▁storing ▁and ▁retr ieving ▁thousands ▁of ▁l ith ographic ▁stones ▁was ▁of ▁course ▁immense ; ▁add ▁to ▁that ▁the ▁cost ▁of ▁the ▁stones ▁– ▁£ 5 ▁each , ▁perhaps ▁$ 1 0 0 0 ▁in ▁today ' s ▁values ▁– ▁and ▁the ▁virtue ▁of ▁saving ▁the ▁art work ▁onto ▁glass ▁phot ographic ▁pl ates ▁maybe ▁ ▁square , ▁and ▁having ▁half - a - do zen ▁stones ▁in ▁stock , ▁which ▁could ▁be ▁clean ed , ▁prepared , ▁and ▁photograph ically ▁emb oss ed ▁over ▁and ▁over ▁again , ▁being ▁res ur fac ed ▁as ▁required , ▁becomes ▁obvious . ▁The ▁time ▁lost ▁in ▁prepar ing ▁the ▁stones ▁went ▁from ▁days ▁or ▁weeks ▁to ▁hours , ▁the ▁lik elihood ▁of ▁error ▁normally ▁att endant ▁in ▁manual ▁copying ▁reduced ▁to ▁pract ically ▁zero , ▁and ▁scaling ▁preserved ▁perfectly . ▁ ▁Im plementation ▁of ▁his ▁in vention ▁was ▁opposed ▁by ▁professional ▁l ith ograph ers , ▁as ▁it