The bottom layer was paper and the top layer was the emulsion or binder and on the paper with two layers it might be collodion, egg-albumen or gelatine.是什么意思_The bottom layer was paper and the top layer was the emulsion or binder and on the paper with two layers it might be collodion, egg-albumen or gelatine.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句