The authors of this artical describe and discuss about analytical laser THUNDER ART technique applied to the diagnostics of archival art work on paper in the case study of Architectural Blueprint done by Nikola Krasnov (1864-1939) that belongs to the collection of The Archives of Yugoslavia. Authors particularly wanted to characterize laser cleaning as comfortable and effective technique for the process of impurities removal in the conservation of works on paper. Obtained results had shown that green wavelength had removed only repainted parts of colors, mostly red and black.U ovom radu razmatra se upotreba lasera u konzervaciji papira na primjeru arhitektonskog crteža na ozalidu arhitekta Nikole Krasnova (1864.-1939.) koji se čuva u Arhivu Jugoslavije u Beogradu. Crtež je čišćen laserom THUNDER ART sa sve tri valne dužine, a najbolje se pokazala zelena koja je uklonila upravo preslikane dijelove boja, ponajviše crvenu i crnu, zbog kojih je i provedeno ovo čišćenje. Autori zaključuju da je lasersko čišćenje udobna i učinkovita tehnika uklanjanja nečistoća u postupku konzervacije djela na papiru
