Wednesday, 31 October 2012

OUGD504 // Design for Print // Book 2 content

-   Set up of print
- Printing processes
- Printing techniques
- Stock

Set up of print
A designer communicates the printing requirements for the design through the print order, this also includes the printing processes to be used, the stock, print run and any special finishes.

-       Understanding print order
A print order is the sequence in which the different colours within a design are laid down and printed within the printing process. For the CMYK printing process, the order in which the ink is laid down is- Cyan, Magenta, Yellow and then black. Within the CMYK printing ink, ‘K’ refers to black but does actually stand for KEY; this is because all the other colours use black to ‘key’ to when registered.
The acronym CMYK implies the order in which the colours are printed, but printers will sometimes change this order when they have seen the artwork. This is often changed if a design contains large areas of flat colour or overprints.

-       Standard printing
A standard print would print a CMYK document in the order of Cyan, Magenta, Yellow and finally Black. If the inks are printed in a different order then it could cause the design to printed wrong and not display the colours how they should be.
In some instances, changing the order of the inks is needed to get an accurate print and to get the best quality of the print. If a large area of one colour is used within a design, this would often be printed first, then following that the CMYK process would follow, printing in the acronym order. Depending on the colours used in a design, the most dominant colour would be printed last. For instance if a yellow or orange was dominant; yellow would be printed last to act as a seal for the print. Black can sometimes print leaving uneven patches and pickering problems, hence printing it between the colours this wont happen.

-       Printing imposition
The imposition plan will plot where the different pages of a design will print. This plan also takes into consideration how it will be printed and folded. The imposition plan is important for the printer as it will determine what method to print the document in.
Printing methods:
- Sheet work – printing one side of a sheet of paper, turning it over and printing the other side with a separate plate.
- Work and Turn – printing one side of a sheet, turning it from front to back and printing the second side with the same sheet-edge alignment on the press.
- Work and tumble – Both sides of a sheet are set on one plate. The sheet is printed and turned over side to side to be printed again.
- Work and Twist – printing one half of the sheet, turning it 180 degrees and then going back through to print the other side.

Printing Processes
Printing is a process that applies ink from printing plates to a paper stock through the application of pressure.
- Offset Lithography
A printing process through which the inked image from a printing plate is transferred or offset on to a rubber blanket roller, this is then pressed against the paper stock. Lithography uses a smooth printing plate and uses the basis of oil and water, which repel each other. When the plates pass under the ink roller, the non-image areas have a water-based film, which repel the oily ink that has stuck to the image areas.
Lithography produces good photographic reproduction and fine line work on a variety of stocks. The printing plates are easy to prepare and high speeds are achievable with this machine, making it a low-cost printing method.
This process is available in sheet-fed presses and continuous web presses. The sheet-fed presses are used for lower production runs such as flyers, brochures and magazines. Web printing is used for high volume printing such as newspapers, magazines and reports.

- Web Offset
The difference between web offset and lithographic printing is that web offset uses a continuous roll of stock. This generates high printing speeds and lower cost per print for the higher volume printing jobs. Web offset printing is most commonly used with rotogravure and flexography because the printing plates used on these are more durable.

Add problems, if enough room

- Flexography
This printing process uses flexible printing plates made from either rubber or plastic. The inked plates have a slightly raised image; these are then rotated on a cylinder, which transfers the image to the stock. Flexography uses fast-drying inks, it is a high-speed print process and can print on to many types of absorbent and non-absorbent materials.
First developed for printing packaging materials, this process was traditionally a lower quality reproduction method, but it now competes with lithography and gravure.
Flexography has been widely used as a quick and economical way of applying simple designs and areas of colour to a wide variety of packaging materials, such as paper and plastic containers (including waxed-paper ones), corrugated-cardboard boxes, tape, envelopes, and metal foil.

- Gravure
This is a more common commercial print process, it happens by an image being engraved into a copper printing plate, this is then pressed directly onto the substrate.
The copper printing plate is created by using a laser or diamond tool to engrave the chosen image into it. Once it has been engraved, it holds the ink and transfers it to the stock. A separate plate is created for each colour separation within the design.
Gravure is a high speed printing process that can give the highest production volume; it is used for very large print jobs.

-       Pad Printing
Pad printing is a printing process that can transfer a 2-D image onto a 3-D object. This is accomplished by using an indirect offset (gravure) printing process that involves an image being transferred from the cliché via a silicone pad onto a substrate. Pad printing is used for printing on otherwise impossible products.
Pad printing is used for one off prints and also large runs; it is applied to medical, automotive, appliances and other products. It is a very adaptable process and can be used across lots of different media.

-       Digital
Digital printing is the process of printing from a digital based image directly to a variety of stock. The process is used for small job runs, which are printed, from desktop publishing software and other digital sources using large format and/or high volume laser or inkjet printers.
The advantage of digital print is that there are no printing plates, therefore the process is a lot quicker and cheaper to print the artwork, but the quality of the print isn’t as good.

Printing Techniques
- Letterpress
This is a method of relief printing whereby movable type is locked into a bed of a press; it is inked, and then rolled or pressed paper against a substrate to form an impression.
Letterpress was the first commercial printing method and was the source for many of the modern printing processes today.
Letterpress is made up of moveable type, which is made from single type blocks, cast lines or engraved plates. The type blocks are all different typefaces, so comprise of letterforms, numbers and characters.
To use the type blocks, you would create a sentence/block of writing with the letterforms and then lock them into the bed, ready to print.
In todays industry letterpress is still used but is seen to be a bespoke technique; it is used on short run jobs for the more decorative trades. To make the process work for the industry it is now used within a rotary press, this works in exactly the same way except it is a lot easier and can be reproduced at a higher volume.

- Screen printing
Screen printing is a printing method, which presses ink through a mesh screen. The mesh screen holds the design, which is either done by a stencil or by covering it in an impermeable substance, which covers the blank spaces allowing ink to be pressed through the openings to transfer onto the stock and show the design.
This process is a slow and low volume method, but it can be applied to a range of different substrates. The process allows specific colours to be applied and also be used to create a raised surface to add a tactile element to the design.

- Wood Block Printing
Block Printing is one of the oldest methods of printmaking and has been around for thousands of years. Since there is such a long history of block printing, there are lots of different techniques, but it is basically using a carved material coated in ink to transfer an image on to stock. The blocks used to print with can be made from wood, linoleum, rubber and other materials.
Designs that are printed with this technique are usually much bolder, since the blocks are carved by hand; there is less detail and more texture to transferred image.
Block printing is also referred as “relief printing” because the ink leaves a raised texture on the paper.  This is different to letterpress because with that process the image transferred leaves an indent on the paper; as block printing is done by hand, the ink sits on the surface adding a raised texture to the paper.
- Monoprinting
Monoprinting is a process that involves images, lines, textures and type that can only be made once; it is not reproduced.
A monoprint is created by building up layers within the design, this could be done through using screen printing, but also different craft materials such as graphite pencil, water colours, woodblock stamps. Each layer would be created on a screen and then transferred onto the stock by using printing medium or ink. Throughout the process the designer can make changes to each layer; adding elements or taking them away, this is how only one design can be produced.
Out of all the printing techniques this is most art influenced technique and isn’t used that much within graphic design, mainly because it is very time consuming and only one design an be done at a time. This technique could be used for a one off print, but as a commercial process it is not up to that standard
- Laser cutting

When printing a design or job the designer must select the stock to be printed on, this must be selected right as it can change the appearance and feel of the printed work. The designer must think about the design and objective of the work and make sure the stock will support and enhance the work.

Stock Qualities
When selecting and using a stock for printing you must look at the physical characteristics of the paper; the GSM, grain and paper direction.
-  GSM
Stands for grams per square meter. This is a weight measuring system that is part of the paper specification; it is based upon the weight of the paper for a square meter. The higher the GSM value is, the thicker and heavier a piece of paper will feel.

- Paper Grain
Paper produced on paper machine has a grain because the fibres from which it is made line up during the manufacturing process in the direction that it passes through the papermaking machine.  The grain is the direction in which most of the fibres lay. This characteristic means that paper is easier to fold, bend or tear along its grain direction.

- Direction
The direction of fibres in printing paper for laser printers typically have a grain that runs parallel to the long side of the paper. This is so the paper can pass through the printer easier.

Paper Types
Many different types of paper stock are available for any designer to use. Using a variety of paper stocks within one design can add to it and make it more interesting. Every stock has different printability characteristics and costs, which is something you must take into account. The main characteristics that affect printability are smoothness, absorbency, opacity and ink holdout.

- Smoothness
The smooth surface of these stocks is created through the used of filler elements. These are usually polished with calendaring rollers. This type of paper stock is typically glossy

- Absorbency
Stocks have different absorbency levels, which refer to the amount of ink that can penetrate the paper. Printing inks will dry quicker on absorbent stocks, as the paper will absorb the ink into it meaning there is less to dry on top, but this can cause problems with the print finish such as dot gain.

- Opacity
Opacity is used to describe the extent to which whatever is printed on one side of the paper shows through and is visible on the other side. It is measuring how easy light can pass through the paper. A high opacity paper stock will have no show through.

- Ink Holdout
This is the degree to which a stock resists ink penetration because of its lack of absorbency. Coated stocks will be prone to this as the ink sits on the surface of the stock, which increases the drying time.

Types of stocks
-       Coated paper
Paper with a clay or other coating applied to one or both sides. Coated papers are available in gloss, silk, or matt finish and are used for projects requiring a fine finish.
Coated paper generally produces sharper, brighter images and has better reflectivity than uncoated paper.
Used to print brochures, leaflets and posters. Typically used for high volume print runs.

-       Uncoated paper
Paper that doesn’t have any kind of coating applied is uncoated paper. Through not having a coating this stock is not as smooth as a coated page. There are many different finishes, colours and weights available with this type of paper and is generally a more absorbent stock.
Used for business stationery and in laser printers. Uncoated papers are usually used in conjunction with coated paper, to add extra texture to a project or on its own, as it is more cost effective.

-       Wove
Paper made on a closely woven wire roller or mold. It has a faint mesh pattern within the grain of the paper. This paper type is popular for stationery and book publishing.

-       Laid
Laid paper is a premium quality paper stock with a textured pattern of parallel lines within the grain. Commonly used for business stationery.

-       Bond
This is a economic, uncoated woven paper, often used for copying or in laser printers. A high quality bond stock would be used for letterheads

-       Antique
A high quality paper with a clay coating on both sides, leaving the paper with a textured finish. The stock is available with a rough or matt surface and is typically used to add texture to a design or publication. This stock would be good for halftones or a design that have a lot of definition and detail.

-       Artboard
Uncoated, stiff board. Typically used as a cover stock for publications.
-       Cartridge
A thick white paper, with a stiff feel. This stock is used a lot with artists and mainly within sketchbooks as ink and pencil drawings are produced well on it. The stock has a textured finish to it. Used mainly for sketchbooks, stationery and annual reports

-       Chromo
A waterproof coating is applied to one side of this stock to allow for embossing and varnishing processes to be used. This stock can be glossy or matt. Used for labels, wrappings and covers.

-       Greyboard
Lined or unlined board made from waste paper. It has a rough texture, good bulk and is grey in colour. Used for packaging material or covers for publications.

-       Mechanical
Produced using wood pulp and acidic chemicals, this paper is suitable for short term use as it yellows and fades quickly. It has a higher brightness and smoothness than newsprint, but it is uncoated, with a matt finish. The stock is used for newspapers and directories.

-       NCR
A carbonless coating to make duplicate copies. By applying pressure to the stock paper is will transfer the markings to a second layer of stock below.  Used for forms and purchase orders.

-       Newsprint
Made primarily of mechanically ground wood pulp, this is the cheapest paper than can withstand standard printing processes. It has a short life span and reproduction of colour is low quality. Used for newspapers and comics.

-       Plike
A rubbery substrate used for cover stock and flyers.

Sustainability within stocks
Sustainability is a key concern for many clients and consumers and plays a big part of commercial printing as so much paper is used but also wasted.
Many companies now opt for a more sustainable product that has used recycled products to produce the stock. This is reducing their environmental impact on the world, but still being able to have the printed products needed.

-       Sustainable printing
Sustainable printing is now an ever-growing concept within the printing industry as more and more companies are opting for this type of product. Many printers specialize in offering this environmentally friendly service.
Most people would think that sustainable printing just involves using a recycled stock paper, but it goes much further than that. Specialist sustainable printers will use chlorine-free paper, ‘waterless’ technology within the printing process and environmentally friendly inks, along with recycled paper. Not only is the use of sustainable products and printing processes reducing the impact, but graphic designer and clients can both contribute to this as well.
Graphic designers have a huge part in this, as they are the ones, which specify the print job. Simple changes to how a graphic designer works can also help, these could include, reducing point size to fit more text to a page, send PDF’s instead of print outs and sourcing the print estimate at the start of a job as there could be ways to save cost through changing formats etc.
Clients can also be more environmentally friendly too, they can specify from the start they want to use a sustainable stock/ink. The best way they can contribute to the reduce in waste within commercial printing is by providing a more accurate print run; thousands of over prints are wasted and thrown away by print companies everyday because the client didn’t need as much. Other ways involve the use of smaller formats and minimizing the use of different finishing techniques.
Throughout every stage of the printing process there are ways that sustainable products can be used, but also the mind set clients, designers and printers can all add to becoming a more environmental world. 

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