## 2 Materials and Methods
### Analysis Results and Findings  
The results obtained from the SPME-GC/MS measurements allow the analysis of off-gassing chemicals inside the closed original film boxes or cans and, therefore, can give essential findings about the composition of the atmosphere inside such a film box. The samples tested comprise several naturally aged historical film samples of various deterioration stages on cellulose acetate base, with different types of film materials (positive, negative, black and white, color). The variety of out-gassing chemicals is large and inconsistent and reflects all aspects of the history of the individual film roll:  
* Original composition;
* Chemicals used within the development process (to a minor extent);
* Storage conditions and their influences on chemical degradation;
* Actual deterioration stage;
* Treatment during use and long-time storage (e.g., influences from cleaning chemicals, chemicals added for preservation issues, etc. );
* Influence of long-time storage container (ventilated vs. non ventilated, inert materials vs. chemically reactive materials, etc.). To a minor extent, the measurement process itself gives variations in results, due to the influence of the position of the SPME fiber, the RH and temperature during sampling. Both factors were minimized to the best possible extent, e.g., RH and temperature were kept constant and stable for all measurements as well as for storage of the film samples (controlled and documented storage conditions, access storage, 20 \({}^{\circ}\)C/45%RH), and the fibers were positioned in close contact on similar and comparable positions on the respective film rolls. As an example, the SPME-GC/MS chromatograms of two films are reported in Figures 1 and 2. The first figure shows the SPME-GC/MS chromatogram analysis results obtained from sample SCS-00060-5, cellulose acetate based black and white positive film, (manufacturer: Perutz, dated 1953) in a comparatively low deterioration stage (A-D strip level 1.5). Interestingly, phenol and camphor show high peaks, followed by the peak regions of alkanes and phthalates. A toluene peak is detected in the neighboring area. Figure 2 shows the SPME-GC/MS chromatogram analysis results obtained from sample DFF_12_584, a 16 mm cellulose acetate based black and white positive film, in a low deterioration stage (A-D strip level 1.5-2). A butanol peak is detected in the direct neighboring area of acetic acid, and besides phenol and plasticizers (phthalates), a high amount of naphthalene was detected. With cellulose acetate films, in many cases, some chemicals show higher peaks (and, therefore, higher levels, according to the semi-quantitative measuring method) than acetic acid. It is interesting to note that in several samples very high amounts of naphthalene were present, most probably a decomposition byproduct of diacetate films, where monochromorphathalene was used as a plasticizer. It can also be assumed that naphthalene was used as insecticide, respectively as a protective chemical. To summarize the results, a high and diverse variety of chemicals was detected. This fact is a very important finding, because in practice this means that film material of the same charge, manufacturer and period can be developed, stored, used, and treated differently during its history of use and, in combination with the numerous decomposition byproducts, therefore can evaporate different chemicals. The variety of the chemicals detected is large enough to be detected in the literature, and the number of chemicals detected in the literature are not known. Figure 1: Solid-phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (SPME-GC/MS) chromatogram analysis results obtained from sample SCS-00060-5, a 35 mm cellulose acetate-based black and white positive film. Figure 2: SPME-GC/MS chromatogram analysis results obtained from sample DFF_12_584, a 16 mm cellulose acetate based black and white positive film (manufacturer: Voigtlaender, dated 1943/44).