Use of bacterial cellulose in degraded paper restoration: Effect on visual appearance of printed paper

Abstract

One of the most common methods used to reinforce damaged paper is to apply a lining, using Japanese paper (JP). The reinforcing material must consolidate the paper without modifying its visual appearance. The unique properties of bacterial cellulose (BC) suggest that it could be efficiently used to reinforce degraded paper documents. The changes in the visual appearances of the printed commercial papers lined with BC and JP were examined in this study. Four commercial papers, coated and uncoated, were printed with cyan, magenta, yellow, and black offset inks. The printed samples were lined with BC and JP sheets. Print density, gloss, and CIELab coordinates were tested in the lined and unlined samples before and after aging. Lining with JP notably affected the print density and CIELab coordinates. The lining with BC resulted in lower decrements in color intensity. The gloss values of samples lined with BC differed widely amongst the papers, whereas in papers reinforced with JP these values never exceeded 6%. Subjecting the samples to an aging process did not markedly modify the results except for the BC-lined samples, in which color differences increased.

Nanocelluloses and Their Applications in Conservation and Restoration of Historical Documents

“…One of the methods used by conservators to restore damaged paper is the application of a reinforcing layer on the paper surface, known as lining, which allows the loss of mechanical resistance to be recovered (Bansa and Ishii, 1997). The material typically used for this purpose is Japanese Paper which provides a high resistance, but it is not entirely satisfactory for all documents because the sheets are not very homogeneous (Gómez et al, 2017). Nanocelluloses have emerged as a novel and innovative approach in the conservation and restoration of paper documents because they can solve many challenges such as structural weaknesses, pH instability, moisture exposure and damage repair.…”

A Review of Applications of Nanocellulose to Preserve and Protect Cultural Heritage Wood, Paintings, and Historical Papers

“…However, with these treatments, the damaged areas of paper were consolidated, as visible in Figure 9, and the results of the application of BNC and CNF suspensions were comparable with the adhesive consolidation; they did not alter the visual appearance of ancient papers, even in the long term, and permitted an innovative approach for paper stabilization. Other research works, such as those reported by Gomez et al [96] and Santos et al [97,98], showed the use of bacterial nanocellulose (BNC) for the paper reinforcement as a replacement of the usual Japanese paper coating method, obtaining excellent results in terms of the minimum thickness of the coating and better legibility of the characters after processing, although with a slight yellowing of the surface due to the aging process. Moreover, the treatment with BNC decreased the wettability due to the reduction in air permeance, an important aspect that prevents the formation of mold.…”

“…Bergamonti et al [16] proposed a new treatment for the conservation and consolidation of ancient papers based on the use of cellulose nanocrystals (CNCs) with the addition of silver (Ag) nanoparticles in order to obtain both a consolidating action due to nanocellulose and biocidal activity by Ag nanoparticles (Figure 10). Other research works, such as those reported by Gomez et al [96] and Santos et al [97,98], showed the use of bacterial nanocellulose (BNC) for the paper reinforcement as a replacement of the usual Japanese paper coating method, obtaining excellent results in terms of the minimum thickness of the coating and better legibility of the characters after processing, although with a slight yellowing of the surface due to the aging process. Moreover, the treatment with BNC decreased the wettability due to the reduction in air permeance, an important aspect that prevents the formation of mold.…”