Appunti per l'esame di Printing / Tecniche di Stampa - in inglese

APPUNTI PRINTINGINKS- liquid paste

Two types of inks = ( uid and watery) and (thick an tacky);- vehicle, pigment

Inks are made of three types of substances = a a and a variety ofadditivedi erent types of (like driers);- Printing inks = liquid, paste, water or organic solvent based, radiation curing inks, etc;- drying mechanism,

There are di erent depending on many factors = 1) printingmethod; 2) type of printing ink; 3) speed of printing machines; 4) printing substrates; 5)type of printed product; 6) characteristics of the dryer system;

COLORED COLORS

Process color = 1) referred to CMYK, four-colour process, 4C process or just‘process’; 2) to reproduce it, the le is separated into four colours - Cyan, Magenta,Yellow, Black; 3) when they are printed on paper, the original image is recreated; 4)during the separation = screen tints made of small dots are applied at di erent anglesfor each of the four colors; then, they are transferred to four di erent printing plate andrun on a

printing press with one color over the other one;

result: it seems a continuous tone;

Spot color:

1. created without screens or dots;
2. example: pantone matching system (spot or solid color);
3. spot colours are used in logos and identity programs.

THE PANTONE MATCHING SYSTEM:

• 18 basic colours that can be mixed up, a palette of creating a unique shape, with a unique name or number followed by either a C (=Coated paper) or a U (=Uncoated paper);
• Pantone Specialty Solid Colors: Pantone metallics, pantone premium metallics, pantone pastels & neons;
• CMYK / Four Color process, coated or uncoated;
• Process simulations of Solid Pantone Colors: Pantone color bridge coated or uncoated; Pantone extended gamut coated guide (#);
• Extended Gamut(#): they allow you to get a broader color gamut (CMYK PLUS Orange, Green and Violet); when you add 'em, you can achieve a much closer match to the traditional formulated spot ink colours.

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APPUNTI PRINTING

PAPER- printing

Substrates stocks: a term used for any surface to be printed, on which ink will adhere. They can be paper, plastics, foil, metal, cloth, or any other surface.

Papers can be:

1. Natural
2. Paper felt marked
3. Textured

Paper features:

1. Grammage or weight
2. Size (sheets dimensions)
3. Bulk
4. Grain

Grammage or weight: Paper is expressed in grammes per square meter (gr/m2). Paper starts from 40 g/m2 to 225 gr/m2, cardboards are more than 225 gr/m2.

Size: Paper sizes include A0, A1, A2, A3, A4, A5, A6, A7, A8; B0, B1, B2, B3, B4, B5, B6, etc. Normally, paper is sold packaged in stacks of 250 or 500 sheets, or even in reels.

Bulk: The thickness of a paper sheet, also known as caliper. In book production, it is essential to determine the size of the book. The bulk is determined by many different variables in the paper making process (amount of refining, the rate at which wet pulp is deposited on the wire, etc.). Calculation: spine in mm = ((n° pages/2) x grammage x bulk) / 1000.

Paper grain = the direction of fibers in a sheet or web of paper, generated during paper formation = as paper moves forward along the forming wire on a papermaking machine, the fibers align in a direction parallel to the wire travel in the machine (also called machine direction);

- long-grain when the paper is cut into sheets, it will be 1) (or grain-long) if the fibers are aligned parallel to the long edge of the sheet, 2) or (or grain-short) if the fibers are aligned parallel to the short edge;

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- paper will tear and fold more easily with the grain and with greater difficulty against the grain;

- Grain direction = important aspect 1) in printing processes such as sheetfed offset lithography (in particular multiple-color work), especially in connection with dimensional stability, 2) on how well a particular sheet of paper will retain its original length and width upon exposure to moisture;

- The direction of greater dimensional change will be in the cross-grain direction;

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saddlestitching, …BOXFOLDING- For paper and cardboard products that must be converted into shaped objects (foldingboxes, coated boxes, folders, displayers, posters, etc);- Operations: die cutting, folding and gluing, handmade operations to produce boxesand containers in general;- It is the main stage to finish packaging products;- Packaging = refers to all those activities related to designing, evaluating andproducing the container for a product, it is where the product is stored, it protects itfrom any physical damage and at the same time attracting customers and building thebrand equity;- Layer of packaging = the product might have three layers of packaging = example:toothpaste comes in a plastic tube (primary package), then it is packed into acardboard box (secondary package) and finally it is packed in a corrugated box(shipping or third package);- Typical packaging boxes market = cosmetics boxes, jewelry boxes, gift boxes, foodboxes, e-commerce boxes, electronic products boxes,

…- Packaging boxes technical work ow:

1. Packaging design (artwork and die cutting design);
2. Packaging approval process (3D rendering, digital printing and cutting);
3. Prepress (layout, colour management, imposition, platemaking);
4. Printing and decoration (hot foil stamping);
5. Die cutting;
6. Folding and gluing.

- Finishing = all the operations required to nish the nal product and ship it: packaging, strapping, stretch lm wrapping, palletizing, addressing, mailing...

APPUNTI PRINTING

PRINTING PROCESSES

• printing = one of the most importante steps in the graphic work ow, during which we can see the concrete result of the printed product;
• printing stock ink, printing plateFour elements are required: the (=substrate), the the printing press;(=master) and

IMPACT PRINTING PROCESSES

• the printing pressure determines ink transferring from image carrier to substrate;
• Letterpress, exography, o set, gravure, screen printing, pad printing;

NON IMPACT PRINTING

1. Digital imaging
2. Electrophotography
3. Inkjet
4. HP ElectroInk (hybrid process)

1. Any image that exists as a series of small dots with different sizes
2. Serves to simulate the appearance of continuous gradations of tone

closely together produce dark areas (shadows);

LETTERPRESS- the most traditional of printing processes;

- mainly used to apply decorative e ect like hot foil or embossing;

- based on raised graphics, made by metal or photopolymer plate = letterpress is a reliefprinting process (=relief printing can also be used to refer to exography);

- inking rolls pass over the plate, touching the reliefs; then, the image is transferred bypressing the plate on the substrate.

OFFSET LITHOGRAPHY (LYTHO OFFSET)- the inked image is transferred (or “o set”) from a plate to a rubber blanket, then to theprinting substrate;fi fl ff ff ff ff ff ff fl fl- when used in combination with the lithographic process (=based on the repulsion of oiland water), the o set technique employs a at (planographic) image carrier (plate) onwhich the image to be printed obtains ink from ink rollers, while the non-printing areaattracts a water-based lm (called “fountain solution”), keeping the non-printing

areasink-free;- the widest spread process, available either sheetfed or webfed;- high quality products of several sizes;- Application eld = printed editorials and commercials in small and large runs, labels,paper and cardboard packaging;

FLEXOGRAPHY (FLEXO)- it is increasing dramatically for its technical features;- relief printing form (printing areas in relief) but soft;- web fed printing presses;- quality on paper lower than o set but good printability on exible stocks;- application eld: exible packaging, labels, shopper, corrugated cardboard;- A form of printing that uses exible rubber relief plates and highly volatile, fast-dryinginks to print on a variety of substrates absorbent e non-absorbent (plastic lms, paper,cardboard, ...) commonly used in exible packaging on cardboard packaging;- the image to be printed is rested on a rubber-based printing plate (clich ), which ispositioned around web press cylinders that rotates; the plate is inked, with the inkedimage being moved to the

printing surface afterwards;

- Flexo printing = 1) a great choice if a high volume order with high-quality result is required; 2) compared to digital printing, it has very high initial costs and longer preparation of printing machines;

GRAVURE (ROTOGRAVURE)- it uses engraved cylinders or cylinder-mounted plates as the image carriers;

- the image areas are etched into the surface of the cylinder as a collection of tiny cells; the cylinder rotates in an ink fountain and ink collects in the cells, the excess ink being scraped from the non-image areas by a doctor blade; the paper (or other substrate) is passed between the gr