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The Archive range is specially designed for long life by
incorporating several very important features:
- Surface sized with gelatine starch
- Woodfree pulp which gives high strength
- Alkali buffering with calcium carbonate to give
protection against atmospheric acidity (currently about pH4 in London)
- Not using conventional alum/rosin sizing but a special
sizing which is neutral pH to ensure an acid free paper
The long life of the paper is demonstrated by subjecting
it to accelerated ageing at high temperature and testing for tear resistance
and folding endurance. These attributes make it ideal for documents and records
which are required to be preserved for posterity. Its suitability for storage
in a library for hundreds of years is shown by a typical set of performance
specifications:
| Substance |
85g/m2 |
| Caliper |
103 microns |
| Opacity |
89.0% EEL |
| Smoothness |
200ml/min Bendtsen |
| Ash |
10% (including
minimum
2% calcium carbonate) |
| Tear |
620mN (machine
direction) |
| Aged Tear Retention |
80% MIT |
| Fold |
2200 (500g cross
direction) |
| Aged Fold Retention |
45% |
| pH (Hot Extract) |
9.4 |
| Furnish |
100% bleached chemical
woodpulp |
These results enable the paper to be classified as a
permanent or long-life paper as defined in the American National standard
Z39.48 - 1984 and greatly exceeds ISO9706 |