The thickness of PVDF is mainly determined by electrospinning time, which is another important factor in conservation process.Fibers did not form a stable film to protect paper at shorter times,and the appearance of the paper would be influenced by thicker membranes produced after a longer spinning time since PVDF is white itself. We spun for 1–5 min to form PVDF membranes of different thickness directly on paper samples as the protection process and measured the thickness and color changes (E) as Table 2 showed.