OH CROP Design for Print Manual

ContentPrint ProcessesStockFinishing TechniquesPaper Sizes

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OFFSET LITHOGRAPHYOffset lithography is a process used for printing on a flat surface, using printing plates. An image is transferred to a printing plate, which can be made of a variety of materials such as metal or paper. The plate is then chemically treated so that only image areas (such as type, colors, shapes and other elements) will accept ink. Water and ink is applied to the plate. Because of the chemical treatment, ink only “sticks” to the image areas, which reject the water. Areas without images reject the ink. The plate is then rolled onto a rubber cylinder applying the inked area, and in turn the rubber cylinder (or “blanket”) applies the image to the paper. The system is “offset” because the plate does not come in direct contact with the paper, which preserves the quality of the plate.

WEB OFFSET

GRAVUREThe plates have an indented image which holds the ink. The image is achieved by engraving or etching. Spirit inks are used which dry very quickly. This is ideal for fast run-ning high volume print runs such as magazines, packaging, wall paper and stamps. It can also be used for the reproduction of fine art images.

Web presses are mainly used for printing maga-zines and other similar publications. Paper is fed through the press from a continuous roll or ‘web’ of paper. Web presses can print up to 40,000, 32 page sections per hour. The paper is automatically cut folded and stacked into sections as it is printed.

SCREEN PRINTING

Stencils can be produced photographically or by hand. One colour is printed at a time and much of it is done on hand operated presses. The main advantage of screen printing is its versatility. It can be used to print on almost any material, including wood, glass, metal, plastics and fabrics.

FLEXOGRAPHY

Flexography is a form of printing process which utilizes a flexible relief plate. It is essentially a modern version of letterpress which can be used for printing on almost any type of substrate, in-cluding plastic, metallic films, cellophane, and paper. It is widely used for printing on the non-po-rous substrates required for various types of food packaging (it is also well suited for printing large areas of solid color).metal, plastics and fabrics.

Pad printing is a printing process that can transfer a 2-D image onto a 3-D object. This is accomplished using an indirect offset (gravure) printing pro-cess that involves an image being trans-ferred from the cliché via a silicone pad onto a substrate. Pad printing is used for printing on otherwise impossible products in many industries including medical, automotive, promotional, ap-parel, and electronic objects, as well as appliances, sports equipment and toys.

PAD PRINTING

STOCKWhen it comes to printing one of the first thing you need to decide is which paper you choose. The thickness of the paper is quite import-ant. Thicker paper is more durable, conveys different message and of course in most cases more expensive. To find an optimum solu-tion look at the list of the general usage of different paper density:

90 - 100 gsm - used for stationery, magazines, booklets, flyers and brochures.

120 - 170 gsm - used for text booklets, flyers and brochures.

200 - 250 gsm - ideal for magazine and booklet covers

280 - 420 gsm - used for cards of all sorts and book and booklet covers

FINISHING TECHNIQUES

SCORING AND PERFORATING

Heavier Boards need to be scored before folding. Papers with weight over 170gsm should be scored to avoid the spine cracking. Scoring and perforat-ing can either be done during printing or when die-cutting.

DIE CUTTINGDIE STAMPINGDie stamping is a process which gives a raised printed image. It can be used on areas without ink to blind emboss. The image stands out in relief and is created using two dies, A ‘male’ and a ‘female’. One die forces the paper into the other to make an embossed image.

If the job is an irregular shape (such as a folder with pockets) and can-not be guillotined it will need to be die cut. A form is made from sharp knives which are embedded in wood. The knives follow the shape of the outside of the folder. Blunt knives will crease and score. The form is then registered with the printed sheet and shape is punched out.

STITCHING

PERFECT BINDING

Perfect bound books are trimmed on the spine and the pages glued in place. Most paperback books and thicker magazines are perfect bound.

Saddle stitch binding is the simplest way to bind books in our time. This method is used to bind notebooks, brochures, pamphlets, and other small books. This is a common type of book binding, and one that you will see this type of binding every-day.

VARNISHING

Varnish is a sealant applied after printing, that can be gloss or matt (offline varnishing). Some printing presses can varnish at the same time as the print run (inline varnishing or aqua seal) although the effect is not as pronounced as offline varnishing. The varnish seals the ink into onto the paper so that it does not set off. Varnish can be printed in small areas for creative design effects (spot varnish), using a plate just as a colour would be printed. When a small amount of colour is mixed with the varnish, an interesting subtle effect can be obtained.

EMBOSSING

Embossing refers to the creation of an impres-sion of some kind of design, decoration, letter-ing or pattern on another surface like paper, cloth, metal and even leather, to make a relief. In regular printing or an engraving, plates are pressed against the surface to leave an imprint. In embossing however, the pressing raises the surfaces adding a new dimension to the object

FOIL BLOCKINGA metal die is pressed onto the material to be printed through metal-lic foil. Blocking is available in black, white or other colours, in ad-dition to the traditional gold and silver. metal, plastics and fabrics.

PAPER SIZESMany paper size standards conventions have existed at different times and in different countries. Today there is one widespread international ISO standard (including A4, B3, C4, etc.) and a local standard used in North America (including letter, legal, ledger, etc.). The paper sizes affect writing paper, stationery, cards, and some printed documents. The standards also have related sizes for envelopes.

PRINT MANUAL