Oksana Plotnikova: Investigation and conservation of Latvian Republic passports (1927 - 1943)

The paper describes the study of the covers and the paper of Latvian Republic passports from the period 1927-1943, which were stored for a long time under unsuitable conditions. The fibre composition, pH value and microbiological destruction of papers were determined, and the conservation of some passports was carried out.

After the assessment of the physical condition and visual inspection of passports, it was found that they correspond to the 1st preservation level, which is assigned to severely damaged units to be stored, i.e., documents with pronounced paper and information medium damage which may cause the loss of the document’s physical integrity or complete decomposition as well as irreversible loss of information, and documents with low potential longevity. Among them most of the passports (34 units) are „irreversibly damaged” due to mildew and moisture.

The cover of the passports is calico that consists of a base – flax fabric of linen weave, impregnated probably with latex. The paper of the cover was made of cotton and flax fibres and glued with a starch-casein size to the flax fabric.

SEM and citochemical (Hercberg reagent) analyses have shown that the composition of the paper of the passport has flax, cotton and maybe some wood cellulose fibres. But the flax fibres are the main fibres in the paper composition. The paper is covered with a thick coat and a layer of printed dye (grey) in the form of an ornamental design.

Frequently, some parts of the paper and the cover material have been destroyed to a great extent due to the effect of water and micro-organisms. SEM images of the cover and the paper at the magnitude about 6000 have revealed a great content of different micro-organisms.

The pH value was determined for the paper of nine passports. The obtained pH measurements range was 4.27 to 5.71. The mean pH values for the paper were 4.81 - 5.45. The obtained pH value clearly shows the damage degree. After the passport conservation (neutralization) pH values were 6.5 – 6.8.

In the first quarter of 2008 microbiological testing of passports was carried out. Six test samples were taken from the surface of the each object. During the preventive inspection, it was found that the above-mentioned objects contained visible black and green colour coating and patina, many pages in the passports were agglutinated and the smell characteristic to mould could be felt. Varied microflora, dangerous to the paper medium, was detected on the objects; the prevailing genus of microorganisms (Penicillium sp., Alternaria, Oidium, Cladosporium, Trichoderm sp.) belongs to micromycetes, which both chemically (releasing ferments, breaking the structure of cellulose) and mechanically destroyed the fibres, rapidly causing an irreversible biodestruction of paper. Microscopic analysis of the passport paper with SEM and a light microscope shows that the paper is interwoven with hypha. Thus, it was necessary to use aggressive disinfection agents. The method chosen for the process of conservation was fumigation in a disinfection chamber, where the passports were kept for 14 days and held in formaldehyde vapour. After disinfection, the passports were aired for 10 days.

The microbiological testing of passports was carried out repeatedly. Four test samples were taken from the surfaces of the objects. During the inspection, it was found that there are viable bacteria and fungi on the objects. The results of control tests show that both qualitative and quantitative pollution with spores of microorganisms is within standard limits. At the same time, bacteria do not influence the degradation of the paper. It can be seen from the tests performed that the disinfection was successful.

After examination, seven passports were disassembled from the block, and corroded rivets were removed.

Then mechanical cleaning was performed. The methylcellulose water solution was used to remove the dirt, patina and white mould stains from the covers of the passport. After that the passport paper was strengthened in two ways. Those being in the worst condition were processed with the aerosol Bookkeeper by spraying it. The second type of strengthening was applied to the passport paper in better condition. These paper pages were put into a chalk bath. Neutralization of the paper was repeated 2-3 times, depending on the acidity of paper. After that the pages were dried and pressed.

After neutralization, the passport pages were reinforced with 0.5% methylcellulose water solution. Then filling and reinforcement of the lost places of the passport pages was performed with Japanese paper - Japan Kinkgawa and Seidenpapier using wheat starch glue.