Cellulose acetate film plasticized with diethyl phthalate was subjected to artificial aging regimes and the loss of plasticizer determined by means of Thermogravimetric Analysis and Fourier-transform Infrared Spectroscopy. Alterations in the strain hardening capability of the films was monitored by Dynamic Mechanical Analysis, and the connection between flexibility, strain hardening and the degree of plasticization investigated as a means of monitoring the physical condition of archival cellulose acetate film. It was found that the higher the plasticizer content the greater the ability to strain harden, and therefore the least vulnerable to mechanical damage from archival handling. The correlation between the critical plasticizer content and the working properties of cellulose acetate film provides a means of assessing stability, and highlights artifacts at risk from physical damage

Light emitting diodes (LEDs) are steadily finding application in an increasing number of museums and heritage institutions, providing energy-efficient solutions for collections display. Although there is a business case to be made for moving toward LED lighting, the safe display of objects must also be ensured. Identifying vulnerable pigments and paints ensures that future preservation strategies will be put in place, avoiding acerbation of damage and reducing the need for conservation. In the first part of our research we investigate color shift and molecular alterations in three yellow paints, namely, lead chromate sulfate, arsenic sulfide, and cadmium sulfide in linseed oil and gum arabic binders. Following an artificial aging regime, color shift was evaluated using colorimetry and molecular alterations were monitored using attenuated total reflectance–Fourier transform infrared spectroscopy coupled with multivariate analysis. Up to 80 Mlux h the lead chromate samples in linseed oil displayed equivalent color shifts approximating 10 ∆E₀₀ on exposure to the three artificial aging regimes. Color shift has been attributed to the formation of lead oxides evidenced by the appearance of a mid-infrared spectral band at 470 cm⁻¹ assigned to PbO₂. Above 80 Mlux h the formation of lead oxides was exacerbated by exposure to one particular LED. Arsenic sulfide in linseed oil displayed color shifts intensified by both types of LED. Above 40 Mlux h there was a discernible color shift in all samples, with the two LEDs displaying ∆E₀₀ values two times higher than those displayed by the tungsten halogen samples. The alterations have been attributed to the formation of As₂O₃, which is known to form in the presence of wavelengths shorter than 428 nm. Cadmium sulfides in both linseed oil and gum arabic paints did not display discernible color shifts or the presence of degradation products.

Cellulose diacetate and cellulose triacetate cels from animated feature films in the collection of the Walt Disney Animation Research Library were tested by several analytical techniques in order to assess their composition and look for evidence of degradation. Triphenyl phosphate and a range of phthalate plasticizers were identified using pyrolysis-gas chromatography/mass spectrometry, which also showed evidence that evaporation of more volatile plasticizers may have occurred. Plasticizer content measurements by solvent extraction, found to be more accurate than volatile content data from thermogravimetric analysis, revealed there was less residual plasticizer in triacetate cels compared to diacetate cels. Gas chromatography/mass spectrometry, performed to quantify the acetyl content of cels after removal of plasticizers by solvent extraction, revealed some evidence for hydrolysis of the oldest cels, although the reduction could be related to original variations in acetate content from the polymer manufacturers. Use of Fourier-transform infrared spectroscopy to measure deacetylation of the cellulose acetate polymer based on the hydroxyl to carbonyl peak area ratio proved less satisfactory. Moreover, because the cels cannot be measured directly due to interference from plasticizers, non-invasive assessment of deacetylation using a portable instrument would be impossible. The results from this analytical survey provide an important point of reference against which long-term changes in cel composition can be monitored