One of these is the release of palmitic acid, a white waxy substance. Acetate discs are very susceptible to fungus growth. Excess heat will probably accelerate the loss of the coating adhesion. Vulcanite discs are adversely affected by elevated levels of light, heat and humidity. In response to light and heat, Vulcanite loses sulfur.
Light induces oxidation and form oxides of sulfur and sulfuric acid in the presence of humidity.
The acidity builds up to a level at which the degrading material is attacked and eventually decomposed. 15 Shellac discs High humidity levels accelerate the embrittlement of shellac discs. This embrittlement causes a fine powder to be shed from the disc after each playback, effectively scraping away groove information. Organic materials in the aggregates are susceptible to fungus attack, while shellac itself is said to be fungus-resistant. The consequence of thermal cycling is that each cycle of temperature results in a small irreversible deformation, and these deformations are cumulative.