Search

Film-based cellulose nitrate negatives are a unique class of objects that contain important information about life, historical buildings, and the natural landscapes of past years. Increased sensitivity to storage conditions makes these objects highly flammable and can lead to irretrievable loss. In this regard, timely identification of the degradation process is a necessary step towards further conservation and restoration. This work studies the possibility of detecting the degradation process based on cellulose nitrate artifact yellowing. A total of 20 normal and 20 yellowed negatives from the collection of Karl Kosse (The State Museum and Exhibition Center ROSPHOTO) were selected as objects for statistical study. The novelty of this work is in its demonstration of the possibility to divide negatives into normal and yellowed areas with different shades based on different B/R and B/G ratios of both light and dark negatives, i.e., regardless of the distribution of RGB component values for the obtained digital photo from the negative. Moreover, the obtained differentiation result was demonstrated for individual image pixels, without the need for averaging over a certain area. [ABSTRACT FROM AUTHOR]

Photographic artifacts carry important historical and cultural information. Materials used in photography at the turn of the XIXth and XXth centuries tend to degrade both over time and if the temperature and humidity conditions of storage are violated. In this connection, the question arises of determining the safety degree and monitoring the condition of photographic materials. Close attention should be paid to photographic materials that become flammable as a result of decomposition. This class of objects includes photographic films based on cellulose nitrate. This study was aimed at examining 100 negatives and stereonegatives from the collection of Karl Kosse dating from 1902 to 1917 as typical examples of these hazard class objects. The degradation of individual negatives was accompanied by a significant change in color—yellowing. The base of photographic negatives (cellulose nitrate and camphor) was determined by Raman spectroscopy, and the presence of a gelatin layer was determined by ATR-FTIR spectroscopy. Using chemometric analysis methods based on the RGB components of digital photos of negatives, an approach has been proposed for determining the state of degradation. The use of the support vector machine approach allows for obtaining a decision boundary, which can be later used to analyze a large data array. [ABSTRACT FROM AUTHOR]