[求助]黑白攝影如何提高鏡頭的對比度？ [復(fù)制鏈接]

閱讀光學(xué)文獻(xiàn)時(shí)對其中的“enlarging on paper with hard gradation”無法理解，求大神指教，謝謝！ Y-\/Y*;cd  
“When black-and-white photography was still dominant, one could compensate the low contrast reproduction of these lenses by enlarging on paper with hard gradation.”