Monitoring emissions from cellulose nitrate and cellulose acetate costume accessories: An evaluation of ph indicator dyes on paper, cotton tape and cotton threads

This article reports on an evaluation of simple and inexpensive techniques for monitoring ‘off‐gassing’ from costume accessories, which may be made with cellulose nitrate (CN) and cellulose acetate (CA). As they degrade, CN and CA produce acidic emissions, which not only accelerate the decomposition process of the objects themselves but also promote the fading of dyes and the degradation of nearby objects. pH indicator dyes, namely cresol red, cresol purple, Congo red, methyl orange and cochineal, applied to paper, cotton tape and threads, were tested for their suitability and then for their usefulness in monitoring a collection of 15 hair accessories, one of CA, one of tortoiseshell and 13 of CN, and three fans. As well as a cresol type recommended by another author (Julia Fenn) for the lower pH emissions from CN, it is suggested that Congo red or methyl orange for the higher pH emissions from CA should be used simultaneously. It was noted that cotton tape and cotton thread exhibited better resi...