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The 4 Common Printing Methods

The 4 Common Printing Methods. Intaglio or gravure , e.g., etching Relief , e.g., letterpress Stencil , e.g., silkscreen Planographic , e.g., offset lithography. Planography: prints what is drawn on the surface. Relief: prints what is left on the original surface. Intaglio:

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The 4 Common Printing Methods

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  1. The 4 Common Printing Methods • Intaglio or gravure, e.g., etching • Relief, e.g., letterpress • Stencil, e.g., silkscreen • Planographic, e.g., offset lithography Planography: prints what is drawn on the surface Relief: prints what is left on the original surface Intaglio: prints what is below the surface Stencil: prints through open areas in a screen Encyclopaedia Britannica Online, U of MN Libraries

  2. Intaglio An image is cut (engraved) into the surface of a (usually copper) plate.(Note: modern, commercial printing techniques use a photochemical process to produce printing plates.) Ink is rubbed into the surface and wiped off to leave ink only in the grooves below the surface. Paper is pressed (under high pressure) on the plate and picks up the ink. Examples include etching, engraving, mezzotint, aquatint, drypoint, and modern rotogravure printing. Encyclopaedia Britannica Online, U of MN Libraries

  3. http://marinaterauds.com

  4. Relief The opposite of intaglio in that the printing surface is cut or etched in such a way that all that remains of the original surface is the design to be printed. Examples include woodcut, linocut, metalcut, and letterpress printing. www.hotbedpress.org Encyclopaedia Britannica Online, U of MN Libraries

  5. Stencil Also known as silk screening, screen printing, or serigraphy. Consists of forcing ink, by pressing with a squeegee, through the mesh of a netting screen stretched on a frame, onto the object to be printed. The nonprinting areas of the screen are protected by a cutout stencil or by blocking up the mesh. Encyclopaedia Britannica Online, U of MN Libraries

  6. Planographic Employs the property that grease and water are immiscible. Ink is applied to a grease-treated image on the flat printing surface. Nonimage (blank) areas, which hold moisture, repel the lithographic ink. This inked surface is then printed—either directly on paper, by means of a special press (as in most fine-art printmaking), or onto a rubber cylinder (as in commercial offset lithography). Encyclopaedia Britannica Online, U of MN Libraries

  7. Offset lithography • Original artwork - photographs, illustrations and text - are scanned and entered into a computer. • These are combined into a document using page lay-out software. • Full size films are output using a high-resolution imagesetter. • Metal plates are prepared from the negative of the artwork using photochemical techniques. The plates are exposed to high-intensity light through the films and then chemically treated so that non-image areas are water absorbent. http://www.bobs.co.uk/print/Offset.html

  8. Offset lithography • Water is used to repel the oily ink from the non-printing area (white areas); the printable areas are receptive to the ink. • The metal plate is fastened around one of 3 cylinders (the plate cylinder). • The ink is then transferred or “offset” to a 2nd, hard rubber blanket cylinder. • Finally, the ink is offset to paper via a 3rd or impression cylinder. Paper is fed as individual sheets or via large rolls or “webs.” http://www.bobs.co.uk/print/Offset.html

  9. Offset lithography The smooth rubber blanket cylinder produces crisp, smooth, clean edges. Almost any texture of paper or color of ink can be used. This is the most economical and high-quality method commonly available. http://www.bobs.co.uk/print/Offset.html

  10. Line Art Printing

  11. Line art is illustration that contains only solid black lines or dots, and includes line and ink, stippling, hatching, scratchboard, and Coquille board It is easy to reproduce accurately and inexpensively, usually by the “offset” printing process.

  12. Halftone Printing

  13. Continuous-tone illustrations (or black and white photographs) are reproduced through a halftone screen printing process: • Illustration is photographed through a fine screen grid of 150-200 dots per inch (up to 300 possible), which breaks the light into tiny dots • Gray areas are broken into black dots—small dots for light values, medium dots for middle values, large dots for dark values • Producing good halftones is technically demanding and expensive

  14. http://www.descreen.net/eng/help/descreen/images/screen_sample.jpghttp://www.descreen.net/eng/help/descreen/images/screen_sample.jpg

  15. Very fine lines may be lost or appear broken. • Lightly shaded pencil drawings or barely discernible gradations are difficult to reproduce. • No absolute white is reproduced. • A halftone or scan of a previously published halftone will produce a moiré effect. http://commons.wikimedia.org/wiki/Image:Moire-(quadrat)-2.png

  16. Four-Color Process Printing Y C M

  17. Original artwork is photographed using separate filters to screen for each of the 4 colors: • Cyan printer • Magenta printer • Yellow printer • Black printer (added to overcome muddiness of dark tones) (K= the “key color” or black) • Each color is interpreted separately in a dot pattern on a screen grid; small dots for light values, medium dots for middle values, large dots for dark values.

  18. Each colored dot takes its place in a rosette. Each screen is angled very slightly at a carefully predetermined degree to avoid superimposing the dots on one another and creating a moiré pattern. Properly registered screens produce a “rosette” pattern. Halftone screen with black ink Halftone screens with process inks http://livedocs.adobe.com/en_US/Photoshop/10.0/WSfd1234e1c4b69f30ea53e41001031ab64-7798.html

  19. The human eye blends the dots together so they appear as smooth gradations of color. The finer the grid pattern or screen (more dots per square inch), the truer the print is to the original. In offset printing, a spot color is any color generated by an ink (pure or mixed) that is printed using an additional screen(s) (CMYK + spot color)

  20. C M Y K

  21. As scientific illustrations, your work is intended for publication—plan accordingly! • Journal? • Size of original? • Amount of reduction? • Line art, halftone, or color? • Quality of reproduction? • Cost of reproduction? • Printing process?

  22. References and recommended readings • The Guild Handbook, chapters 6, 9, 10 • Wood, chapters 5, 6, 10 • Zweifel, chapter 1 • Chavez, C. 2010. Real World Adobe Photoshop CS5. Peachpit Press. • McCleary, R. 2009. CMYK 2.0: A Cooperative Workflow for Photographers, Designers, and Printers. Peachpit Press. • Encyclopaedia Britannica Online, U of MN Libraries

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