Paper Packaging for the Long-term Preservation of Photographic Plates
| Hlavní autori: | , , , |
|---|---|
| Médium: | Článok |
| Jazyk: | angličtina slovenčina |
| ISSN: | ISSN 0034-5806 |
| On-line prístup: | http://www.viks.sk/chk/res_2_94_79_93.doc |
| Abstrakt: | Conclusions. To conclude, only sample G passes all the tests. Sample F is suitable in all respects except that of initial pH values, its level being lower than the limit laid down by the ANSI standard. The magnitudes for which it is considered essential to set maximum or minimum limits in assessing the suitability of paper for photographic-plate packaging of the type that we advise are the following: weight per unit area, folding endurance, tearing resistance, pH, polymerization degree, alpha-cellulose content and the nature of the fibrous pulp. In order to assess paper stability over time, it is also necessary to calculate the variations after accelerated aging in whiteness degree, folding endurance, pH and polymerization degree. While certain characteristics (types of sizing, absence of metallic particles, sulphurs, peroxides, etc.) indicated in the standards were not examined, they are in any case regarded as essential in assessing the suitability of this type of permanent packaging. With regard to metallic particles, it is worth considering the proposals put forward by the Joint Working Party CARTA/DIAM: iron content below 100 ppm and copper content below 20 ppm. Maximum values should also be set for the other substances involved as the photographic activity test proves to be unreliable. The results obtained suggest that moist-heat aging can be limited to 30 days, but not that this method is to be preferred to the dry-heat test. Summaries. Seven different kinds of paper, intended by their producers for long-term preservation, are tested for some qualities related to their use for packaging photographic glass plates (liber, ash content, alkaline reserve, air permeability) and for changes in folding endurance, tearing resistance, pH, DP and whiteness provoked by different kinds of accelerated aging (80°C 65%, 105°C dry). |
|---|---|
| ISSN: | ISSN 0034-5806 |
