英语六级阅读考试题样题解析 K) Paper is also commonly made from cotton and rag waste. This has the advantage of being lignin-free, but because there is much less cotton and rag than trees, it also tends to be much more expensive than wood pulp paper. You will still need to purchase from a reliable source though, since even rag paper and card can contain undesirable additives. L) A reliable source for quality rag papers is a recognized art stockiest. Many water color artists insist on using only fine quality rag paper and board. M) The main lesson to learn from this information is that you cannot rely on purchasing archival materials from the high street. The only safe solution is to purchase from specialist suppliers. It may cost rather more, but in the end you will know that your important and valuable data and images have the best home possible. 1. The corn-flake packet is cheaper than high grade card. 2. There are a lot of materials which can be used for making paper, but the superiority ones are soft wood, cotton and rags. 3. During the whole manufacturing process, the final product is made from a pulp of cellulose fibres. 4. In order to make white paper and card, the makers will add bleach. 5. Liguin is essential for the tree but it will make paper easy to break. 6. Many paper producers will preserve lignin during manufacture, because leaving the lignin will make more paper from a tree. 7. Acid is particularly harmful to photographic materials. 8. If the lignin is removed from the paper, the paper will be more expensive. 9. Although free of lignin, paper made from cotton and rag waste can also cost more money than wood pulp paper because there is much less cotton and...
