For long-term preservation of important or sensitive economic, cultural and historical data, physical media are still among the most favorable storage systems. Microfilms containing silver halides are independent from technological progress and are expected to have a lifetime of several hundreds of years, given appropriate temperature and humidity. However, if conditions aren’t ideal for some amount of time, the films can be susceptible to microbiological and biochemical degradations or physical damage, e.g. layer ablation, potentially causing loss of data.

To further improve the stability, and thus, lifetime of microfilms, two different approaches were pursued in the presented study. Approach 1: To aid the adhesion of the gelatin layer, which contains the optically active particles, to the substrate layer, consisting of polyethylene terephthalate (PET), nitrogen-based bonding agents were introduced to the surface of the PET substrate during atmospheric plasma treatment. A significant improvement of the adhesion could be shown. Approach 2: The antimicrobial properties of the protective outer gelatin layer were addressed by adding essential oils of oregano, thyme, and lemongrass to the gelatin. Essential oils were chosen as a more economically and health friendly alternative to phenol, which is commonly used as an antimicrobial agent. The results of both approaches will be shown and discussed in the presentation.