Design for Print// Content for Print Processes

Digital Print

Modern printing methods such as laser and ink-jet printing are known as digital printing. In digital printing, an image is sent straight to the printer using digital files such as PDFs and those from graphic software such as Illustrator or Indesign. This eliminates the need for a printing plate, which is used in offset printing, which in a result can save you time and money. It usually refers to professional printing where small run jobs from desktop publishing and other digital sources are printed using large format and/or high volume laser or inkjet printers. Digital printing has a higher cost per page than more traditional offset printing methods but this price is usually offset by the cost saving in avoiding all the technical steps in between needed to make printing plates. Without the need to create a plate, digital printing has ended up bringing fast turnaround times on demand. Instead of having to print large, pre determined runs, requests can be made from as little as just one print. While offset printing still results in slightly better quality prints, digital methods are being worked on at a fast rate to improve quality at lower costs. 

Flexography 

Flexography is used for printing on materials such as foil, acetate, plastic and other materials  used in packaging. Flexography used flexible printing plates that are made of rubber or plastic. These inked plates with a slightly raised image are rotated on a cylinder which transfers the image to the substrate, as you can see on the diagram above. Flexography uses fast-drying inks, its in all a high speed print process. It can print on many types of absorbent and non-absorbant materials  and can print continuous patterns, for example gift wrap and wallpaper. Some other typical print jobs are paper and plastic bags, milk cartons, disposable cups and wrappers. Flexography printing may also be used for envelopes, labels and newspapers.

Advantages. 

• It can print on the reverse side of stretchable, transparent films.
• It can perform coating and in-line laminating operations.
• It is cost effective for many applications.
• It enables fast turnaround time between jobs.
• It can do short-run work profitably.
• Presses can produce in-line, pressure sensitive labels in a continuous operation.
• Presses can produce many types of projects requiring down line finishing such as:  diecutting, kiss cutting, scoring, perforating, embossing, hole punching, etc.

Lithography 

Lithography refers to a lithograph print that is made from an image which has been applied to a flat surface. Traditionally this flat surface was a specially prepared lime stone, but today grained aluminium-printing plates and the original stones are used. The process is based on the fact that oil repels water. An image is drawn, painted or photographically applied the stone or plate using a greasy medium. The image will repel water and accept ink. Lithographic inks are oil based. 

The plate is placed on a special press and is then rolled up with either leather or rubber rollers. Paper is then placed on the print and is run through the press by hand. Like many other printing processes one colour at a time is printed.

Lithography is a very versatile printing technique and artists can get the medium to suit the needs of their particular style. It can be subtle with many layers of washes or it can look like a pencil drawing with strong lines that pick up the texture of the drawing tool and the "tooth" of the plate. It can have large areas of flat colour or else areas can be "scratched" into. With a skilled master printer to guide the artist almost any effect is possible.

What can it print on?

 Many commercially-printed books, brochures, business forms, catalogues, labels, letterhead, newspapers, magazines, posters, product packaging and stationery are produced using offset lithography. Other printing methods include flexographic, gravure, screen and digital or nonimpact printing. Lithography is popular due to its low cost and versatility, and the high quality of its results, which have smooth, clear images with no impressions left on the page.

Gravure 

This is an expensive but high quality printing technique that uses direct contact between an etched copper plate and the paper. While the plate has a relatively high cost, this technique is the best way to print high quality, large volume materials such as brochures, magazines, annual reports and mail order catalogues.Gravure is a high quality printing process capable of producing printed images which have a continuous tone effect similar to a photograph. The gravure process utilizes a metal printing cylinder onto which the image is etched. The gravure cylinder can be created with analog or digital plating processes. Gravure is used for many packaging applications, magazines, and pressure sensitive labels. Gravure is the preferred method of producing magazines and catalogs that have large circulations. An example of a high volume, high quality publication that utilizes rotogravure is the "National Geographic" magazine.There are also many specialty items that are created with rotogravure including gift wrap, wallpaper, plastic laminates, printed upholstery, imitation wood grain finishes, and vinyl flooring. Many of the specialty items are printed on very wide presses. Some of them, such as those that print patterns on floor coverings, are up to 150 inches wide.A gravure sheet-fed process is used for smaller runs for such items as limited edition prints and other artwork, photographic books, high denomination postage stamps, stock certificates, and some advertising  pieces.

Screen Print 

Screen printing is one of the early methods of printing. It involves the passing of ink or any other printing medium through a mesh or 'screen' that has been stretched on a frame, and to which a stencil has been applied. The stencil openings determine the image that will thus be imprinted. 

Screen printing was a technique first used by the Chinese almost 2000 years ago. They used human hair stretched across a wooden frame to form the screen. To that they attached a stencil made from leaves stuck together into different shapes. This was probably the first application of screen printing ever. Subsequently, the Japanese adopted the screen printing process and used woven silk to make the mesh and lacquers to make stencils. The use of silk is where screen printing got its alternative name – Silk screening or silk screen printing. In 1907, it was Samuel Simon near Manchester who patented the first ever industrial screen printing process. Many years later close to the First World War, John Pilsworth of San Francisco developed the Selectasine method, which basically introduced the concept of multi-color printing using the same screen. Different areas on the screen were blocked out for different color inks, thus resulting in a multi-colored image. This technique became hugely popular for printing signs and posters in large quantities. From using hair to silk to polymer meshes, screen printing has come a long way today. The basic technique remains the same but with innovation and the introduction of electronics and computers, screen printing is no longer recognizable as the technique Simon patented.  No matter what kind of screen printing machine you have, there is some basic equipment that will be required. The stencil or screen is of prime importance since it determines the design and image output. It refers to the frame, the mesh and the photosensitive material  on which the image is created. The Squeegee is the rubber held in a rigid handle. Ink of course. The substrate refers to the surface on which the design is to be printed. The machine base, which holds the substrate and allows the screen to print on it and is often the base of the entire screen printing unit. Here are some tips on helping you select the best screen printing equipment for your use. The substrate or surface on which screen printing can be carried out are too many to be named. Any surface that can be stretched and printed on is a surface for screen printing. The CD covers you see are all screen printed. Beautiful cotton fabrics, silk and polyesters can all be screen printed on. Posters, signs, flyers, advertisements on buses, t-shirts and even watch dials are screen printed. Thus there are many applications of screen printing.

Letter Press

After the Gutenberg press introduced movable type to the process in the 15th century, letterpress was the predominant printing method for 500 years. The creation of huge rotary presses made industrial printing and newspaper production practical. By the 1950s, xerography and offset printing began to supplant letterpress and by the end of the 20th century,digital printing and related technologies had become the industry standard for many uses. Nevertheless, letterpress is still used for some specialized commercial applications. The old method is also enjoying a resurgence among modern-day enthusiasts who prize the hand-made qualities and historical nature of letterpress print.

Letterpress is the oldest form of printing. In this method, a surface with raised letters is inked and pressed to the surface of the printing substrate to reproduce an image in reverse. Typically, metal type has been used but other possibilities include carved wood or stone blocks.

Risography 

A Risograph machine is a multifunction printing device. Risograph machines are designed to scan, copy and print large quantities at high speeds. They can print up to 120 pages per minute at a price of about one-half cent per copy. This makes printing large quantities from a Risograph machine significantly less expensive than printing from a typical inkjet or laser printer. To make copies, the original document or picture is scanned into the Risograph. The Risograph then creates a master by burning the image (in the form of small spots or holes) into a thermal plate. This master wraps around a drum where the ink is squeezed through the burned image. The drum rotates at a fast speed while papers run through the machine, causing the image to be printed on each sheet of paper. Risograph machines are typically used for high-volume printing and copying from 20 to 5,000 prints. They can be used to print and copy forms, labels, fliers, business cards and newsletters. Risographs can also be connected to a network to print directly from a computer.

• Lenticular 
  

  Lenticular printing is a technology in which lenticular lenses (a technology that is also used for 3D displays) are used to produce printed images with an illusion of depth, or the ability to change or move as the image is viewed from different angles.

  Examples of lenticular printing include prizes given in Cracker Jack snack boxes that showed flip and animation effects such as winking eyes, and modern advertising graphics that change their message depending on the viewing angle. This technology was created in the 1940s but has evolved in recent years to show more motion and increased depth. Originally used mostly in novelty items and commonly called "flicker pictures" or "wiggle pictures," lenticular prints are now being used as a marketing tool to show products in motion. Recent advances in large-format presses have allowed for oversized lenses to be used in lithographic lenticular printing.

  

  
  

  

  
  

  Foil Stamping

Also called hot-die stamping, foil stamping is a method of letterpress printing using a stamping die, heat/pressure and metallic or pigmented film. Foil stamping differs from both engraving and embossing in that it uses a die with its image area in relief; that is, standing up form the surface of the plate. The decorative and useful process of foil stamping has been around longer than the printing press. With the incredible selection of foils available, the possibilities seen endless, and a foil stamp adds a truly refined look and feel to any piece. In hot stamping, an extremely thin ribbon of foil is fed into a press, it releases its pigment onto the paper when pressed between a die and a hard flat surface and heat is applied. A combination of heat and pressure then bonds the leaf material to the paper.

• Metallic: Gloss, Dull and Machined, Pigmented Metallic: Gloss and Dull, Dusted Foil, Pearlized, Clear: Gloss and Dull Marble, Oil/Water Shimmer, Etc.

These are particularly useful for overprinting on dark paper stocks, as nearly all foils are opaque. In addition, there are pastel foils, marbled foils, and dusted foils that give a softer image. The foil you select, of course, depends on the effect you are trying to achieve. Because of their high reflectance, foils are particularly suited for pieces that need to stand out and catch the eye-such as the covers of a paperback books and annual reports.

Pad Printing 
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 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 in many industries including medical, automotive, promotional, apparel, and electronic objects, as well as appliances, sports equipment and toys. It can also be used to deposit functional materials such as conductive inks, adhesives, dyes and lubricants. Physical changes within the ink film both on the cliché and on the pad allow it to leave the etched image area in favor of adhering to the pad, and to subsequently release from the pad in favor of adhering to the substrate. The unique properties of the silicone pad enable it to pick the image up from a flat plane and transfer it to a variety of surfaces, such as flat, cylindrical, spherical, compound angles, textures, concave, or convex surfaces.