Technology Options. This is the third article in this part of the Wild Format Series. It is supported by. Wild Format

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1 The Digital Dots Digital Printing Technology Guides are about providing you with all you need to know about investing in wide format digital printing technology. The Wild Format goal is to create and share objective and independent explanations of key digital production technologies. The articles are relevant for all parts of the graphic arts supply chain, especially print buyers and designers. They re for anyone with great ideas who wants to get them into print cost effectively and conveniently. This is the third article in this part of the Series. It is supported by The guides are intended to expand awareness and understanding of the craziness that can be created on wide format digital printing devices, from floors to lampshades and everything in between. These guides are made possible by a group of manufacturers working together with Digital Dots. Together we hope you enjoy the articles (yes, there will be more) and that you put into practise what you learn. If you want to talk about it, go to our LinkedIn group at Enjoy and Go Wild! Technology Options The basic term 'wide format' covers a huge amount of different digital technologies, but how well do you understand the different options? And how do you know what s best for your company and customers? Wide format digital printing is a mature business sector, which has developed over the last two decades and includes several distinct technologies. It continues to evolve rapidly so it pays to continually evaluate the capabilities of the different printers, inks and consumables to keep up with what can be achieved in the most cost-effective manner. 1

2 Flatbed printers, such as this Screen Truepress Jet W3200, offer high productivity and good image quality for rigid substrates. Photo Nessan Cleary In subsequent sections of these guides we'll explore some of the underlying technologies such as the different types of inks and substrates. But there are a number of basic questions that we'll go through here. The first is whether the graphic is for indoor or outdoor use. Some printers use aqueous inks that are better suited for indoor use as the inks won't stand up to bad weather, though the prints can be laminated. However, aqueous printers are cheaper than outdoor printers and can give very high quality results. They often feature eight or even 12-colour inksets to cover a very wide colour gamut. That said, today's outdoor printers can produce extremely good results and many online photo bureaux use outdoor printers because of the range of materials that they will print on. Of these, solvent inks will work with most media, and are suitable for outdoor applications for several years. Latex is often marketed as an environmentallyfriendly alternative, because the inks are mainly water-based. However, they use an enormous amount of heat energy to dry the water out of the prints. UV-curable ink printers will print to an even wider range of media, including direct to rigid substrates but tend to be more expensive. The printers themselves use either a roll-fed system for handling flexible substrates or a flatbed design for rigid board materials. Most of the smaller roll-fed printers come in a choice of 1.3m and 1.6m widths and can handle many applications from banner 2

3 advertising through to vehicle graphics. media is held still while the print heads There s also a class of superwide printers move across the bed. that are typically 3.2m wide, with some going up to 5m wide, which is ideal for Flatbeds are available in different sizes and printing large banners and building wraps. at different price points from entry level Most of these printers can print either machines up to high volume production across the full width or to two smaller rolls printers capable of challenging screen side by side, each with completely different printers for longer run jobs. The budget images. machines tend to compete on price and image quality, but there are now a number Flexible media can be laminated to boards, of mid-range flatbeds that offer a good but it s generally better to print direct to compromise between image quality and rigid media using a flatbed printer. It s a speed. They also have the advantage of quicker, and therefore cheaper process and lower ink prices, as they use much higher the results are likely to be consistent as the ink volumes. The print heads scan back and forth to build an image so that there s a balance between image quality and productivity. Photo Nessan Cleary 3

4 Small roll-fed printers, such as this Mimaki JV300, offer a good balance of image quality and speed for a relatively small cost. Photo Nessan Cleary Many printers are hybrids capable of passes can improve image quality, it also handling both roll fed and rigid media. slows down production. Thus, much wide But whereas in the past most hybrids were format production involves striking a adapted from roll fed printers and had delicate balance between image quality and tables either side to support rigid media, productivity. For this reason, many people nowadays many flatbed printers offer roll quote a viewing distance for wide format feeding options for handling flexible media. graphics. Thus a poster in a shop will need much higher resolution because customers Most wide format printers use multiple may be standing next to it, whereas a passes to build up an image. This means banner on the side of a building will only be they create a high resolution image by seen from some distance and can be printed filling in gaps in each successive pass. faster with less passes. It also allows the printer to cope with problems such as blocked nozzles that Colours might otherwise cause lines or other In theory the CMYK process colours should artefacts on the image. But while multiple be adequate for producing most colours, 4

5 but many print engines use additional inks, sided window graphics with the white in usually light cyan and light magenta for the middle to prevent show through from better gradients, particularly for areas such one side to the other. as skin tones. Some also have options for extended colour gamuts adding orange, However, white ink has larger pigment violet and green. The downside is that particles than other colours and so tends extra colours add to the cost and may not to slow down the printing. Jobs that use be necessary for graphics viewed from a white ink have to be carefully scheduled distance. in the print queue so as not to delay other work. This is especially the case if the white Many engines also have white as an option. is to be flood coated over the whole job. White ink is essential for some jobs, such as Most digital printers have two white ink window graphics where the white ink can channels to cope with this. White ink tends lay down a backing to enhance the colours. to be more expensive than other colours, Most devices can also print a graphic in and doubly so if two white channels are multiple layers, which allows for double used. In addition, the printheads will dry Superwide printers, like this Fujifilm Uvistar, can hand banners up to 5m wide. Photo Nessan Cleary 5

6 out if the ink isn t used frequently, so many companies prefer to avoid white ink, especially as most substrates are white. That said, white ink can improve colour vibrancy on cheaper and some recycled materials that don t have a pure white facing. In addition, textiles are easily recyclable, making them a much greener alternative. Most of the textile materials used for graphics are a polyester blend and there s a wide range of different materials from banners through to tee-shirts. Some solvent printers also offer metallic effects. Typically these work by using a silver base and then adding process colours to create tints, such as a yellow to create a gold. Many wide format digital print engines also offer varnish, essentially a clear ink, as an option for one channel. This can lead to some interesting tactile effects, if the graphic is meant to be touched, and can highlight parts of the image. It s particularly useful for producing packaging or retail graphics. Many vendors also claim that clear ink offers enhanced protection for the print, though laminating is probably a better option. The main method of textile printing is dye sublimation, which usually involves printing the image first to transfer paper and then using a heat press to fuse the Textile banners are easier to transport and to store than conventional materials like vinyl and, being washable, easier to keep clean for re-use. Textiles Wide format digital printers can print to an enormous range of substrates, which we ll cover in more detail in further stories in this series. But it s worth noting that there is a growing interest in printing display graphics such as banners to textiles, sometimes known as soft signage. Textile banners are easier to transport and to store than conventional materials like vinyl and, being washable, easier to keep clean for re-use. image to the fabric. This process drives ink colourants right into the textile fibres so that the material retains its natural look and feel. However, some digital printers can print direct to the textile. It s also possible to print direct with latex or even UV inks, saving the cost of specialist printers and finishing equipment. The inks tend to sit on the surface, but the results are adequate for flags and banners. 6

7 Workflow software In general wide format workflows are not as advanced as those used in general commercial print. Some printing engines come with their own Raster Image Processor (RIP) and most dealers will recommend or bundle a RIP for each machine sold. RIPs have developed considerably over recent years, becoming digital front end systems that include basic layout tools such as tiling and nesting. Most support colour management. Most Management Information Systems (MIS) and web to print programs can cope with the demands of wide format digital: short runs of non-standard materials and assorted shapes and sizes. Consequently web to print software is becoming more widely used in wide format, for easier job submission, supporting online comment and approval, as well as variable data printing. Finally, it s worth noting that the same basic wide format digital output technology can be used to create a huge range of products, from posters and banners through to free standing point of sale displays, as well as packaging and even some garments such as tee-shirts. This flexibility and scope have helped to fuel wide format digital printing s growth. There really is no limit, only one s imagination. Nessan Cleary The Digital Dots team specialises in consulting and editorial for digital prepress, printing and publishing technologies. This includes research, testing, evaluation and content services for publishers, printers and print buyers. Our Series is the latest in a long line of educational projects for graphic arts professionals, including designers and content originators. We also publish Spindrift, a subscriber supported, monthly journal with readers all over the world and a sharp focus on technology. We work on various ISO committees developing standards for print production and the environment, and we are accredited auditors for ISO and ISO 9001 in the UK and Sweden. You can find out more about us at digitaldots.org. 7