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

我们的社会对形象有着无法满足的渴望。英国印刷业以135亿GB的营业额位居世界第五，雇用了约12.2万人。互联网现在是主要的广告平台，占广告支出的39%，其次是印刷媒体，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·艾夫斯专利的直纹玻璃屏幕，导致了几乎所有今天的图像都被复制为像素化的CMYK打印。历史悠久的工艺，如伍德伯里和利普曼发明的工艺，产生的印花比目前任何商业上可用的都要好得多。这些过程在很大程度上被遗忘了，因为它们在商业上没有竞争力。凭借她在胶体化学、光学和3D打印方面的专业知识，申请者的目标是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生产用于广告、包装、时尚的高质量印刷，同时还包括无法复制的安全功能。通过将历史的、高质量的、连续的色调印刷工艺的原理转变为非冲击印刷，该工艺将摆脱尺寸限制和基材的形状和材料的限制。Woodburytype是第一种，也是唯一一种能够复制真正连续色调的照相技术。这是一张有色素的明胶层的地形图，图像是由这些层中的光吸收产生的。申请人的目标是通过例如喷墨打印的添加工艺来产生层，而不是从板上压印。使用特别配制的油墨和允许多路打印的改进型打印机，然后可以在多种基材和形状上生成连续色调打印。将这一新过程与李普曼摄影相结合，将产生具有内置安全功能的全彩色、非像素化打印过程。利普曼摄影不包含任何染料或颜料，但仍然根据干涉颜色(如在肥皂泡表面观察到的颜色)再现了可能的最大色域。光通过共振腔选择性地反射，使印刷品在不同的视角下改变颜色。这一特征不能通过简单的方法复制，因此可以作为安全特征加以利用。在经典的李普曼摄影中，腔的反射层由被明胶层隔开的非常精细的金属银粒组成。这些层是通过直接摄影过程生成的，这使得李普曼摄影成为一种一次性的方法。在与工业合作伙伴的合作下，申请者的目标是配制两种油墨，一种是透明的，另一种是反光的，并旨在通过非影响的方法打印Lippmann/WoodburyType的混合油墨。混合动力型将没有尺寸限制，并且可以定制。在身份证或驾照上，可以包括Lippmann/Woodburytype作为车主特定的安全特征。通过直接打印来创建空腔将是一个挑战，但存在可以打印并以周期性结构自我组织的材料：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，分子是以螺旋结构组织起来的。当螺旋的间距满足特定条件时，就会产生颜色。最终的印刷品将由各种液晶和包容层组成，这些层将具有额外的功能。电场或磁场可以切换液晶，即打印是可重写的，这可以用作安全特征。通过在精细印刷研究中心主办研究金，实现了印刷和材料专业知识的理想结合，确保了项目的成功。

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.