Abstract

The stains and subsequent treatment of leather are important considerations for conservators in museums, libraries, and archaeological sites. Blood staining is of particular concern because it can weaken the leather fibres underneath and lead to discolouration of historical leather. This study aims to evaluate traditional materials and different gels in the cleaning process of blood stains found on the surfaces of historical leather. Leather samples stained with blood were prepared and exposed to thermal ageing at 80°C to simulate historical stained leather samples. Ethyl alcohol diluted with distilled water at 50% and 70%, and sodium hydroxide at 3% and 5%, were prepared for the study. Additionally, gels such as gellan, laponite and magnetic gels were prepared for evaluation in the cleaning process. The evaluation process for cleaning involved visual assessment, digital USB microscope examination, scanning electron microscope analysis, colour change measurement, pH measurement, and Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR). The results of visual examination and various microscopes showed that mechanical cleaning removes part of the blood stain and does not completely remove it, and sometimes causes scratches. Cleaning with different gels significantly improved the surface appearance of the skin compared to chemical or mechanical cleaning. The results also showed that there was a significant change in colour differences in chemical and mechanical cleaning, and less in cleaning with gels. ATR-FTIR results showed that the use of magnetic gel significantly improved the chemical stability of the treated samples better than traditional cleaning methods. This study recommends using cleaning gels, especially magnetic gel, to clean blood stains from archaeological leather artifacts.