I remembered architects uses a paper , semi transparent and extremelly sensitive to the water. But they come in 60 grams or so , but Russian site claims they were 180 - 200 grams range . It is bleached cellulose plus cotton paper. There are many transparent papers , thick , glass like and yellow tinted. I remember now , I had been read DaVinci notebooks and he was defending a paper which have small ripples covered , I got a copy a brick sized paper catalog and there was transparent papers like glass. 16 years ago , I think industry developed since than. Let me google it.