Woodbury and Lippmann: A new approach to continuous tone and full colour non-impact printing

我们的社会对图像有着无法满足的渴望。英国印刷业是世界第五大印刷业，营业额为135亿英镑，雇佣约12.2万人。互联网现在是广告的主要平台，占广告支出的39%，印刷位居第二，占32%，而且还在快速增长。一项历史性的发展，CMYK半色调工艺和弗雷德里克·艾夫斯（Frederick Ives）专利的玻璃屏幕，导致了几乎所有当今图像的像素化CMYK印刷品的复制。伍德伯里和李普曼发明的那些具有历史意义的工艺，所产生的版画比目前市面上任何东西都要好得多。这些工艺基本上被遗忘了，因为它们没有商业竞争力。申请人凭借其在胶体化学，光学和3D打印方面的专业知识，旨在将这些技术从默默无闻提升到现代发展的前沿。旧印刷技术的新化身将允许为广告，包装，时尚生产高质量的印刷品，同时包括不可能复制的安全功能。通过将历史悠久，高质量，连续色调印刷工艺的原理转移到无冲击印刷，该工艺将摆脱尺寸限制以及基材形状和材料的限制。伍德伯里照相术是第一个，现在仍然是唯一一个可以复制真正连续色调的照相工艺。彩色明胶层的地形打印，图像是由这些层中的光吸收产生的。申请人的目标是通过添加工艺（例如喷墨打印）来生成层，而不是从板上压印。使用特殊配方的油墨和允许多路径打印的改进打印机，可以在多种基材和形状上生成连续色调打印。将这种新工艺与李普曼摄影相结合，将产生一种具有内置安全功能的全彩色、无像素化印刷工艺。李普曼摄影不含任何染料或颜料，但仍然在干涉色的基础上再现最大的色域，就像在肥皂泡表面观察到的那样。光被共振腔选择性地反射，使印刷品在不同的视角下改变颜色。此特性无法通过简单的方法复制，因此可以作为安全特性加以利用。在经典的李普曼摄影中，空腔的反射层由非常细的金属银颗粒组成，由明胶层隔开。这些层是通过直接摄影过程产生的，使李普曼摄影成为一种一次性的方法。申请人与工业伙伴合作，旨在制定两种油墨，一种是透明的，另一种是反射的，并旨在通过非冲击方法打印Lippmann/ Woodburytype混合。混合型没有尺寸限制，可以自定义。在身份证或驾驶执照上，Lippmann/Woodburytype可以作为车主特有的安全功能。通过直接打印制造空腔将是一个挑战，但是存在可以打印并以周期性结构组织自己的材料：例如手性液晶。液晶与光相互作用，是当今大多数显示器的活动层。在手性液晶中，分子按螺旋结构组织。当螺旋的间距满足特定条件时，就会产生颜色。最终的打印将由各种液晶和具有附加功能的容器层组成。电场或磁场可以改变液晶，即指纹是可重写的，这可以作为一种安全特性加以利用。通过在精细印刷研究中心举办奖学金，实现了印刷和材料专业知识的理想结合，保证了项目的成功。

Our society has an unsatisfiable hunger for images. The UK printing industry is the 5th biggest in the world with a turnover of £13.5 billion employing c.122 000 people. The internet is now the main platform for advertising, with 39% of advertising expenditure, print comes second with 32% and is fast growing. A historic development, the CMYK halftone process and the ruled glass screen patented by Frederick Ives, has led to the reproduction of almost all present day images as pixelated CMYK prints. Historic processes, such as those invented by Woodbury and Lippmann produce prints far superior to anything which is commercially available at the present time. Those processes have been largely forgotten as they were not commercially competitive. The applicant, with her expertise in colloidal chemistry, optics and 3D printing, aims to lift those technologies from obscurity to the forefront of modern developments. The new incarnations of old printing technologies will allow production of high quality prints for advertising, packaging, fashion and, at the same time, include impossible to replicate security features. By transferring the principals of historic, high quality, continuous tone printing processes to non-impact printing, the processes will be freed from dimensional restrictions and restrictions of shape and material of the substrate. Woodburytype was the first, and still is the only photomechanical process that can reproduce truly continuous tone. A topographic print of pigmented gelatin layers, the image is generated by the absorption of light in those layers. The applicant aims to generate the layers by an additive process, for example ink jet printing, instead of an imprint from a plate. With especially formulated inks and modified printers which allow multipath printing, the continuous tone print can then be generated on a multitude of substrates and shapes. Combining this new process with Lippmann photography will lead to a full colour, non-pixelated printing process with in-built security features. Lippmann photography does not contain any dyes or pigments, but still reproduce the biggest colour gamut possible on the basis of interference colours like the ones observed on the surface of soap bubbles. Light is selectively reflected by resonance cavities which makes the print change colour under different viewing angles. This characteristic cannot be copied by simple means and can therefore be exploited as a security feature. In classic Lippmann photography, the reflective layers of the cavities consist of very fine metallic silver grains separated by layers of gelatin. The layers are generated by a direct photographic process making Lippmann photography a one-off method. In collaboration with industrial partners, the applicant aims to formulate two inks, one transparent and the other reflective and aims to print a hybrid Lippmann/ Woodburytype by non-impact methods. The hybrid type will have no dimensional restrictions and can be customized. On an ID card or driving license, a Lippmann/Woodburytype could be included as an owner specific security feature. Creating the cavities by direct print will be a challenge, but materials exist which can be printed and organize themselves in periodic structures: chiral liquid crystals for example. Liquid crystals interact with light and are the active layer in most displays today. In chiral liquid crystals the molecules are organized in helical structures. When the spacing of the helix fulfils a specific condition, colour is generated. The final print will consist of a variety of liquid crystal and containment layers which will have additional functionality. An electric or magnetic field can switch the liquid crystal, i.e. the print is rewritable which can be exploited as a security feature. By hosting the fellowship at the Centre for Fine Print research, an ideal combination of printing and material expertise is achieved guaranteeing the success of the project.