The Croatian Academy of Technical Sciences

Vilko Žiljak, Graphic engineering and digital prints, Page 1 of 24

THE CROATIAN ACADEMY OF TECHNICAL SCIENCES

THE ZAGREB UNIVERSITY

dr. Vilko Žiljak

PROFESSOR ON FACULTY OF GRAPHIC ARTS

GRAPHIC ENGINEERING AND DIGITAL PRINTING

PREAMBLE

Ten years ago our country was the first to have the courage to incorporate digital color images into all documents. It is impossible to “unstick”, replace or forge such non-material images. Today almost all the countries in the world use digital processing of document information. Except for a rather good know-how a decade ago, our newly formed state did not have any technique for making documents. Our country was at war then, isolated, a state not yet recognized by the world. Highly qualified graphical engineering could be found only here - in Zagreb. In such circumstances when everything was done with a fresh start, graphical experts had the opportunity to skip the conventional printing methods and to produce documents digitally. It was also then that our money was among the first in the world to be made and designed as computer graphics. The cartography was made digitally in a completely new manner, because all the analogous originals are still abroad. This was an encouragement to give more space to digital technologies in printing. Since then hundreds of engineers have completed such modern studies of printing and they have been implementing digital techniques into practice, i.e. the prepress, design, reproduction photography, printing, finishings, and other final processing.

1. INTRADUCTION

Digital printing development is correlated to computer innovations. Computers have been introduced into graphical and printing systems only when speed and memory capacity were sufficient to process texts and pictures. The memory capacity of a standard color monograph is 10 gigabits. If our intention is to print such a book in one hour, then the other computer parameters are set: the computer speed, printing speed, computer memory, the printer memory and the speed of data transmission in the network between the computer and printer.

Each new computer development introduced improvements into printing as well. Computers make it necessary to integrate systems in the graphical industry: A prepress system, printing system, postpress final processing, graphical preparation. There is a demand for production to become more fruitful, more flexible and transparent. There is also demand to shorten the preparation time in all printing phases and to constantly enter into more and more complicated jobs. A fully automatic work process is being introduced. This makes it possible to have the complete job automatically led, beginning from the moment of order placement, purchase and up to the moment when the final product has been produced. This requires co-operation between the seller, printer and buyer in various fields.

A special problem is the one how to integrate machines made by different producers. It is necessary to create a Graphics Language, a communication language. XML has found itself in the middle of these strivings.

Now, at the beginning of the 21st century, digital printing is being applied widely. During the previous decade digital printing was successful in the black-and-white technique. Color digital printing was present only in certain fields: small runs and individual prints. Graphical engineers in Croatia applied digital printing in all development phases development. We were among the first in the world to have first-class color digital printing. The same may be said of the training that graphical experts got on all levels.

2. CHANGES IN PRINTING INDUSTRY

In printing there has been great changes: new methods of graphic typography have totally pushed out methods and techniques that were used up till ten years ago, now it is happening in the press which is pulling out the automation in processes of binding and finishing. In the same time symbiosis is emerging in new and traditional techniques of printing, the are replenish combining. Strong development of computing relates to the development, changes and new methods in printing. This year a few congresses were taking place, seminars, professional and scientific meeting, as well as the colloquium about new patents in digital printing. Serious discussions were on the issues of fundamental postulates of graphic production. There is a new way to try to analyse, understand and discuss science of colours, the methods of hybrid systems of electronic printing.

Graphic structure and printing was for centuries closed exclusively for specialised activity and schooling of a high manufacture skill. Till the moment of computer usage in graphic production, nothing significantly different has not happen till the Guthenber´s time, although during this five centuries numerous patents were offered. Small steps in graphic techniques were made by the end of the last century by means of offset and machine type setting. Crucial step of changes starts with the computers of eighties of this century. Along with computers there disappears forever many graphic techniques used so far, as well as methods and ways of production. Education has been changed, the old nomenclature of walks of life have been abandoned, new relations between publishers, printers and authors have been arranged.

Printing was during centuries making its own tradition, reliability and stable methods in production and skills. Along with computers all the methods of typesetting to reproduction photography perished. With computers a page layout is solved, corrections, colour separation, proof printing, transferring text and images to log distances, making a printing plate, mining all prepress procedures, and now computers are inside area of printing by which an end has begun for many traditional techniques in printing industry.

Our generation is lucky to be a part of this important historic fracture, to be included in a number of developing and researching chapters that cover fundamental physical - electronic researches, hardware development and software in visual communications and a research in the field of colour - perceiving. The main reason of computer usage in printing was started by mathematicians who found in graphic endless new domain for researches. Usually we put this results into the chapters of “computer graphics”. Products of this researches we experience in unbelievably visual usage from the image for printing to the animation and digital moving picture. Physics and electro-chemistry were left many open questions from the field of electrophotography, magnetography, viscosity of liquid toners, drying and deep-heating toners, penetration of pigments to different materials.

2. 1. Changes with computers

The results, by entering of the computers in graphic printing, are astonishing not on the field of competition yesterdays graphic methods and techniques, but on the offer of solving new products and extension those printing fields which were, using the old techniques in the middle of nowhere.

News, results, changes and consequences of computer application?

- the explosion of colour printing on all publications;

- a number of new mathematic raster shapes in specialised applications;

- digital halftoning on the level of separate image element;

- stohastic rasters with the ability of multiseparation and combined hybrid rasters solution;

- spot separations in tens colour shades;

- colour usage in daily press (which hold greater part of the graphic reproduction and were always an imperative for printing development) with managing and optimization of colour spending on the level of a pixel;

- highly improved quality in printing magazines, based on digital scanning, computer image processing, and usage of digital photocameras;

- the development of GCR, UCR and UCA methods in colour separations;

- optimization in colour and material spending, as well as in exploitation of equipment depending on the edition, usage and quality;

- individualization of image print, by means of a number and a code in long runs;

- programming binding, folding, automation in finishing;

- created digital printing integrated with conventional printing in hybrid and modular graphic systems;

- the ability of connecting the printed material and products with information system for the control and warehousing the goods;

- introducing CDs and DVDs as the main electronic warehouse of all interphases in graphic production.

New computerised printing enables the author and a graphic worker to see, lead and control the complete graphic process from typesetting to printing.

From the middle of eighties we have extraordinary growth of researches and development of computer interfaces in printing industry. Rich diversity of technological processes, direction - based on new relations of pixel, raster, colours and material for printing, has opened a big interest in the research and experimenting which gave more significant results and has changed many relations in graphic profession. There have been opened new applications, so from the paper graphic methods moved over to computer systems, video, animation, drawings and combined techniques where dominate multimedia solutions. Computer systems allow interactive conversions and using the same issue for realisation in different media. Ideas started in graphics can be stretched to video, film, three-dimensional solution and turn back to be improved by a number of iterations, to work out or change the starting conception. These technologies integrate different media and link different know-alls.

Monitor layout of information is the future and the greatest step forward of the graphic profession. This development is in symbiosis with publishing and graphic prepress. All publications prepared for printing have their own electronic presentation. Paper and printing industry has its future in digital printing with new solutions of graphic design. If computer graphics did not interfere in graphic engineering, probably, printing would already be at the end. The look of today printing material thanks only to computer technique which did not only get back, but did also increased the interest of taking over the informations through printing products and an interest for this profession.

2.2. Changes in education of graphic engineers

Computers broke the exclusiveness of graphic skills for a small number of printing workers. We have changed the programs of learning the printing and offered the ability of continuous adjusting lecturing by new technological experiences. The price of the graphic prepress equipment (which by production manners could hardly be compared to those from new printing era - consider only fifteen years), is decreased hundred times. This has pulled out the graphic prepress from printing sections to the desk of the author, journalist and editor, and entered to primary education. “Desktop Publishing” was created. Graphic image and text processing is nowadays prepared under a hand of an expert from almost all professions, and a direct link to this kind of format and printing machine has opened to authors and publishers a new interest in publishing on a paper. Traditional methods of printing include typesetting, image rasterizing, making a printing plate, print and binding. Computer technology has differently ordered these titles, so new professions has emerged, as well as new approach to education. New terminology was created, new procedures of production so this invoked a new demand for basic knowledge supplement, the need for new engineers. Now, graphic prepress employees more workers than before because market wants more complex solutions, attractive, interesting in design which is possible to achieve by today software and hardware, which couldn’t have been realised by means of former techniques.

Computers and automation have changed a structure of employees of the assortment of a graphic product. A few years ago printing was overloaded with several hundreds titles in the profession nomenclature. A graphic product was produced in separated steps and each kind of a production process was asking for different education degree and different qualifications. Today all skills; from typesetter to the repro-photographer and partially a printer - they are all in the same room. That happened in a process of production. Many job flows were optimized as well as working tasks and working places. Production of a graphic product nowadays is only passible if conducted by a hand of one person which manages and operates a printing machine by means of a computer all the way from the idea to the graphic prepress procedures. This is why it is hard to distinguish a border line between the prepress and printing and intersteps in today printing era. There has emerged a modular printing house; where for a certain product utility link of machines is set, and production procedures as well. By this, printing houses are less specialised for a particular group of products or for tight aiming market.

A system of lecturing printing was meant to be changed, in the forma that a printer as single unit controls all the know-how of reprophotography, computer application, digital printing and all the way to finishing the graphic product. Re-qualification here does not mean abandoning old graphic skills, but it by means of extending the knowledge, it means entering safer business and professional life.

Adjusting the machine schedule to the aiming printing task opens the door to dynamic printing house which seeks for workers with wider knowledge by nonstop learning, flexible people which will not allow to be putted in a whatever drawer of the profession nomenclature. Printing industry, similar event happened to informatics and computer application, is entering to global education into the title we have popularly called “computer literacy”. A program of graphic education is extending to many different media and thus giving a chance to all of us to estimate our future orientation. Only, for this area it is hard to find good teachers currently active in refreshing their personal knowledge.

In professional graphic studies and schools there have been introduced attractive subjects; design, ecology, computing, informatics. Their stronger extension takes over hours that should be give to subjects that would process methods and basics of digital printing not excluding the subjects of conventional printing techniques. With digital systems into graphics there enter new people, mostly younger wanting to be included in digital printing industry.

A computer is highly tempting tool and effect of that is that in graphic profession there has been less interest in learning conventional printing techniques. Young people want to be educated only in the direction of new attractive technologies. Soon we shall have less experts in jobs of managing current printing houses and installed departments which will, still, be the most important in book production, of newspapers particularly in processes of packaging.

3. DIGITAL PRINTING

Conventional printing industry was perfect in the quality of eighties and emergence of the digital printing technique in this years was not in the most lucky time and had merely have any chance. Nevertheless, in the last decade of this century we are witnesses that digital printing is successfully solving: high resolution, clean printing surfaces, stable quality, density high key shades, similarity to the original. The development moved towards a few directions, more important one are: with liquid colours (ink jet), dry (deep heated) colours (electrography, ionography, magnetography). Between this technologies there is no competition, they are fulfilling each other, they all have found their field of application in the area of former graphic products and have also largely extended the assortment. As far as the speed is concerned, magnetogrphy has those characteristics of speed that has an offset printing, the development of magnetography each day gives new patents and for now the only failure is existence only black pigment.

3. 1. Sequential printing

Classifications of digital printing techniques: according to the colour transfer to paper (impact / non-impact), according to the force of pressing the plate against the paper, the rest classifications are related to the usage; number of printing units, speed, adjusting the edition, formats, principles of inputting a paper. With digital printing there emerged another classification: according to certain printing plate. Conventional printing reproduces equal prints, while digital printing brings a sequential printing and individualization based on variable printing plate. For example, a book can be printed in a sequences from the first to the last page. Printing plate depends on the memory size of the computer and not on the size of a cylinder of the printing machine.

Digital printing, just because it does not have a physical printing plate, allows each point to be different from the one before according to the content and size. This has opened some new possibilities of managing the printshop and processes of production. It is allow that during the printing of some editions on the same machine a printing of the totally different shape interferes not interrupting the continuing of the first serial. The same machine is used for multiple proofs what guarantees that approved proof will be the same as print of the edition which is totally new event on the way of highly qualitative finished edition. The proof on the final printing machine managed from the computer used for the prepress phase, jumping over a few traditional operations and the most important is to exclude the physically printing plate with which we reduce the time of making the first approved print to continue the printing of edition.