Tsis muaj ntaub qhwv thaum luam "Carbon paper", uas yog yooj yim thiab txuag lub sij hawm rau kev sau ncaj qha, 2-6 nplooj ntawv rau carbon luam, thiab 2-10 nplooj ntawv rau hluav taws xob luam ntawv, uas tuaj yeem txhim kho kev ua haujlwm zoo thiab ua tau raws li cov kev xav tau ntawm modernization.
Kev sau ntawv ntawm daim ntawv yog qhov tseeb, sib txawv, thiab tsis ploj mus, uas tuaj yeem tiv thaiv kev hloov pauv thiab kev coj ua.
Tsis txhob kis tus ntiv tes, khaub ncaws thiab lwm yam ntaub ntawv sau cia, ua kom huv si.
Muaj nyob rau hauv ntau yam xim kom yooj yim txheeb xyuas thiab tuav.
Cov ntawv yog cov khoom zoo, qhov saum npoo yog du thiab du, muaj zog dua 28 grams ntawm cov ntawv xim, tsis yooj yim rau kev puas tsuaj, thiab xim luam ntawv yog ci.
Nws tsis muaj cov khoom tsis zoo thiab cov ntxhiab tsw, nws muaj kev nyab xeeb thiab txhim khu kev qha, thiab cov duab thiab cov ntawv tuaj yeem khaws cia rau ntau tshaj 15 xyoo tom qab kev tsim xim.