Inspired by an interest in finding both a natural material alternative as well as a successful treatment approach to powdering leather surfaces on a Native American object, a comparative study of two novel treatment materials and two established consolidants for leather with red rot was undertaken. Natural material consolidants have been demonstrated to be preferred by tribal members for use on materials other than leather. One of the materials tested as a potential consolidant was neri, an aqueous mucilage most commonly extracted from the roots of the aibika plant that is used in the traditional production of Japanese paper. The other material selected was chitosan, the main derivative of the natural polymer chitin, which has recently been applied in treatments of archaeological silk and paper. The performance of these potential materials as leather consolidants was compared against the performance of established modified organic consolidants, i. e. mixtures of Cellugel and Klucel G with the acrylic wax SC6000. The study focused on evaluating each material's consolidation performance, the visual and physical changes observed on the leather, and the chemical stability of the consolidant following heat and light aging. Although neri proved to have excellent chemical stability, it is not recommended for leather due to unavoidable water content and unsatisfactory working properties. Though chitosan had no adverse effects towards the appearance and feel of the leather, it is not recommended as a consolidant until further research is conducted on its chemical stability. The Klucel G with SC6000 mixture had great application properties but the wax component is questionable due to the opacity change of the aged wax. Cellugel demonstrated the most desirable properties in performance and chemical stability; therefore it was selected as the consolidant for the treatment on the Native American object. Experimental results indicate that the natural materials evaluated may be recommended as alternatives to synthetic consolidants following additional research.
