本帖最后由 鲁提辖 于 2009-12-14 14:51 编辑
http://www.economist.com/sciencetechnology/tq/displaystory.cfm?story_id=15048773
Making ink bulletproof Dec 10th 2009
Ink: Basic ink compositions have remained unchanged for millennia, but some companies think there is still room for improvement
Illustration by Belle Mellor
HAVING recognised the fallibility of human memory, people have been keeping records written with ink for over four millennia. Thanks to the durability of those early inks, the thoughts of our ancestors have been preserved. Indeed, civilisation itself could be said to depend on the persistence of the written word.
Early inkmakers mixed fine black soot with resin and water. Water suspended the soot, keeping the ink runny enough to write with. Once the water evaporated, the resin made the carbon particles stick to paper or papyrus. Today this is called pigment ink, and it remains in use in pens and inkjet printers. Another ancient way to make ink is to use dyes, in which the colour is dissolved rather than suspended in its solvent. The existence of two such venerable yet reliable technologies, however, has not prevented a number of companies from trying to make better inks.
When Newell Rubbermaid, an office- and home-supplies company based in Atlanta, began marketing one of its Uniball pens with a gel-based pigment ink as “fraud resistant” in 2005, it was not expecting a higher than normal level of demand. But thanks to the ink’s durability compared with dye-based inks and smooth writing due to the gel’s low viscosity, sales grew by around 25% a year. Other penmakers followed suit with similar gel inks.
This ink’s durability and fraud resistance arise because the pigment particles are so small that they lodge between the fibres near the surface of the paper, making them impossible to remove without visible damage to the page, says Leighton Davies-Smith, vice-president of research and development at Newell Rubbermaid. Applying solvents like water, acetone or bleach will dissolve most dye-based pen inks, but will not remove the pigment particles. And when it comes to writing cheques or doctors’ prescriptions, an ink’s ability to resist attack is important.
Durability also turns out to have uses in more mundane situations. Nils Miller, a senior “ink and media” scientist at HP, is all too well aware of the irritation caused by the blurring of inkjet ink by highlighter pens. Some of the technology giant’s inks have been modified following discussions with highlighter manufacturers to ensure that one firm’s ink chemistry does not disagree with the other’s.
The company with the reputation for the most “bulletproof” of inks, however, is Noodler’s Ink, a small American firm. The permanence of its inks relies in part on dyes that react with the surface of the paper’s cellulose fibres. Once written, they resist a variety of solvents known to be used by forgers, as well as more mundane solvents like water. The firm’s founder, Nathan Tardif, recounts stories of new customers who had handwritten documents rinsed clean in natural disasters, leaving behind sheets of paper covered with illegible, watery ghosts of their original written contents. He also argues that most industrially manufactured modern inks are too weak in both their colour saturation and durability.
The reputation of Noodler’s inks recently caught the eye of Nicholas Masluk, a graduate student at Yale University’s physics department. Mr Masluk, who has been tinkering with lasers since his high school days, thought he could make Noodler’s ink disappear without harming the paper underneath. He found that many of Noodler’s inks, as well as other fraud-resistant inks, could be removed with diligent use of a laser that he built for a few hundred dollars using parts bought on eBay. Although these inks can resist chemical attack, they can be blasted away by the infra-red output from a laser. Ink removal thus becomes a matter of careful aim and delivery of very short, high-energy bursts.
Mr Masluk contacted Mr Tardif with his discovery, and the two went on to test a variety of inks to see how well they could withstand laser attack. The most resistant of Mr Tardif’s inks was a popular and particularly vivid one called Baystate Blue. But it was not as chemically resilient as others, since many of Mr Tardif’s customers had expressed a need for this particular ink to be removable with bleach in case a fountain pen leaked while in a shirt pocket.
Noodler’s has since developed a new series of inks resistant to both chemical and laser attack, the most durable of which is called, somewhat eccentrically, Bad Belted Kingfisher. Although it seems unlikely that one of his customers would become the target of such high-tech forgery, Mr Tardif wants to maintain his bulletproof reputation and feels compelled to create new inks that can withstand all known attacks.
History holds a lesson for innovators of ink. Iron-gall inks displaced carbon inks because they were less prone to smudging, but they turned out to be corrosive over time. Leonardo da Vinci and Johann Sebastian Bach used iron-gall inks, and their creations have suffered as a result. Ink technologists must hope their novel creations do not inadvertently destroy what they seek to preserve.
墨水也防弹
墨水：传统墨水配方延续千年，但一些制造商正试图改进 四千年来，人类一直用墨水书写记录来辅助人类脆弱的记忆。早期墨水的耐久性使我们能够见证祖先的智慧。可以这么说，书写延续了人类的文明。 早期墨水的配方主要是黑烟灰，松香与水。烟灰颗粒悬浮在水里，水保持墨水的流动性以方便书写，水干之后，松香就将烟灰颗粒固着在纸面上，这就是所谓的颜料墨水。直到今天一些钢笔墨水甚至打印机墨水都在延用这一配方。另一种古典墨水制造配方是所谓的染料墨水，这种墨水的颜色成分是完全溶解在水中而不是类似于颜料墨水的悬浮在水中。这传统的墨水制造方法历史悠久，配方可靠，但并没有阻止新一代的墨水制造商们推陈出新。 ”Newell Rubbermaid”，一家位于亚特兰大的办公室及家庭用品供应商在2005年开始推销一种具有“防伪”功能的胶状颜料墨水 Uni ball pens, 市场反响好于预期，一年的销售增长25%。其他墨水制造商开始跟进。这种墨水有别于染料墨水耐久性与防伪性是由于颜料粉末固着在纸面的纤维之间，不损坏纸张就无法清除，Leighton Davies-Smith ， ”Newell Rubbermaid” 研发部门的负责人如此说明。水，丙酮之类的溶剂，或者漂白粉能清除大部分的染料墨水，但不能够移走颜料墨水的颗粒。但墨水用来写书写支票或者医疗处方的时候，防涂改功能就变得非常重要。
耐久墨水也在平常的工作环境中得到应用。Niles Miller惠普的”Ink and media”资深研究人员，非常恼火于打印机墨水与荧光笔墨水之间的界限越来越模糊。在荧光笔制造商的需求驱动之下，工业原料供应巨头们供应的墨水原料，变得越来越趋同。
Noodler’s Ink以制造“防弹墨水”闻名。Noodler’s Ink的“防弹”原理在于他的染料分子能与纸面纤维发生反应，一旦书写，笔迹能抵抗几乎所有已知的文件伪造方法，例如最简单的浸水。Noodler’s Ink的创始人Nathan Tardif 列举了大量的事实，一些新的客户曾经的手写稿在一些事故之后变成一堆水印模糊，无法辨认的废纸。他还声称，现代墨水在色彩饱和度跟耐久性方面都很弱。
最近著名的墨水制造商Noodler’s Ink ，吸引了Nicholas Masluk的眼球。这位耶鲁大学研究生，从小就喜欢摆弄激光。他认为他可以在不伤到纸面的情况下，让Noodler’s防弹墨水在纸面消失。他花数百美元从ebay上买来零部件，组装成一个激光发射机，反复镭射之下，许多的Noodler’s防弹墨水以及其他的防伪墨水都可以无损纸移除。墨水移除变成了快速高能定点爆破！
Masluk先生告知Tardif先生他的发现。两位先生继续测试各种墨水的耐镭射性能。耐镭射性能最好的居然是Noodler’s的一款非常受欢迎的艳色墨水Baystate blue！但这款墨水并不能抵抗化学侵蚀。应客户的要求，这款墨水设计成可以用漂白粉移除，以防止染上衣物不掉色。
Noodler’s Ink 由此又开发出一个新系列的墨水，既能抵抗化学侵蚀又能抵抗镭射侵蚀，其中最为强悍的被称为Bad Belted Kingfisher。尽管客户遇上如此高科技的文件伪造者的可能性不是太大，Tardif先生还是坚定的维护Noodler’s防弹墨水的声誉，迫切的要创造出新的墨水来跟新的文件伪造手段一较高下。
历史是墨水改革者最好的老师。鞣酸铁墨水代替了碳墨是因为它不会像碳墨一样总能被抹花。但是鞣酸铁墨水却有个缺点，腐蚀性，达芬奇跟巴赫使用鞣酸铁墨水书写的手稿就是明证。墨水设计者一定不会希望他们的设计毁掉他们一直努力试图想保护的。 |
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发表于 2009-12-14 14:42
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