Hibiscus sabdariffa L. calyces’ and argon DBD plasma: potential eco-friendly cleaners for fire-damaged silver gelatin prints

Abstract

PurposeThis paper aims at examining the potentiality of using Hibiscus sabdariffa L. calyces’ (Hs) aqueous extract to remove soot stains from the surface of fire-damaged silver gelatin prints. It further studies the cleaning efficiency and impact of both a contact method and a noncontact method with argon dielectric barrier discharge plasma (DBD Ar. plasma) on the different properties of silver gelatin prints. Accordingly, it prompts using economic, eco-friendly materials and methods in the photograph conservation field.Design/methodology/approachTo achieve the aims of this paper, four silver gelatin prints were stained with soot and treated with the Hs aqueous extract as a contact method and DBD Ar. plasma combined with the aqueous extract as a noncontact method. The assessment was carried out using digital microscopy, atomic force microscopy and spectrophotometer to study the efficiency of the tested treatments and their impact on the surface of the photographs. Fourier transform infrared was used to monitor the state of the binder after cleaning. Furthermore, the pH and the mechanical properties were measured.FindingsThe contact method resulted in lower concentrations of Hs extract that efficiently cleaned the surface without causing any stains or damage to the treated photographs. The noncontact method (plasma with an aqueous extract) proved to be less effective in cleaning and made the binder more susceptible to deterioration.Originality/valueThis paper reveals the success of Hs aqueous extract in cleaning soot on vulnerable photographs' surfaces.