[求助]黑白摄影如何提高镜头的对比度？ [复制链接]

阅读光学文献时对其中的“enlarging on paper with hard gradation”无法理解，求大神指教，谢谢！ ys=2!P-[#  
“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.”