Alaska State Museums Bulletin 58（阿拉斯加国家博物馆公告58岁）.pdf

Alaska State Museums Bulletin 58 November 2012 Contents: Top 13 Reasons We Don’t Use Leather Dressings at the ASM Ask ASM Shaking the Money Tree Spotlight on Grant in Aid Alaska Museums in the News Professional Development/Training Opportunities Intern Report Professional Time Wasting on the Web TOP 13 REASONS WHY WE DON’T USE LEATHER DRESSINGS AT THE ASM By Ellen Carrlee, Conservator 1. FATTY SPEW (or “spue”) is the name given to white bloom or haze on the surface of the leather. When analyzed, this moldy-looking white or yellow substance is usually made of saturated fatty acids like stearates and oleates that come from the chemical breakdown of animal products like Neatsfoot oil. This is illustrated in Tlingit hide armor that was dressed by professionals at the National Parks Service in the late 1960s. The appearance was fine until the 1990s, when snowflake-like white spew appeared all over the surface. This occurred in spite of appropriate environmental conditions. While dressing leather was a widely accepted museum practice in the 1960s and 70s, results like this made museums reconsider. 1 Detail of snowflake-like fatty spew on the surface of hide armor treated with leather dressing. 2. MOLD and other biological deterioration such as bacterial activity and fungi feed on animal fats in many dressings. Remember that mold thrives in conditions of over 70% humidity and 70°F. If dressing traps too much moisture in the leather, mold will be a problem. Not only does fatty spew sometimes look like mold, leather dressing can also promote mold growth. The interior of this kayak has various problems related to repeated oiling with Wesson cooking oil in the 1960s and there is concern some of th