Category
Printing Process:
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Comparison of printing methods |
| printing process |
transfer method |
pressure
applied |
drop size |
dynamic viscosity |
thickness of ink on substrate |
notes |
| Offset printing |
rollers |
1 MPa |
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40–100 Pa·s |
0.5–1.5 µm |
high print quality |
| Rotogravure |
rollers |
3 MPa |
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0.05–0.2 Pa·s |
0.8–8 µm |
thick ink layers possible, excellent image reproduction, edges of letters and lines are jagged |
| Flexography |
rollers |
0.3 MPa |
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0.05–0.5 Pa·s |
0.8–2.5 µm |
moderate quality |
| Letterpress printing |
platen |
10 MPa |
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50–150 Pa·s |
0.5–1.5 µm |
slow drying |
| Screen-printing |
pressing ink through holes in screen |
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<12 µm |
versatile method, low quality |
| Xerography |
electrostatics |
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5–10 µm |
thick ink |
| Inkjet printer |
thermal |
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5–30 pl |
1–5 Pa·s |
<0.5 µm |
special paper required to reduce bleeding |
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About color printing
Color printing or Colour printing is the reproduction of an image or text in color. Any natural scene or color photograph can be optically and physiologically dissected into three Primary Colors, red, green and blue, roughly equal amounts of which give rise to the perception of white, and different proportions of which give rise to the visual sensations of all other colors. The additive combination of any two primary colors in roughly equal proportion gives rise to the perception of a Secondary Color. For example, red and green yields yellow, red and blue yields magenta, and green and blue yield cyan. Only yellow is counter-intuitive. Yellow, cyan and magenta are merely the "basic" secondary colors: unequal mixtures of the primaries give rise to perception of many other colors all of which may be considered "tertiary."
Modern printing technology
Offset printing
is a widely used printing technique where the inked image is transferred (or "offset") from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a film of water, keeping the non-printing areas ink-free.
Flexography
used for packaging, labels, newspapers.
Inkjet printing
used typically to print a small number of books or packaging, and also to print a variety of materials from high quality papers simulate offset printing, to floor tiles; Inkjet is also used to apply mailing addresses to direct mail pieces.
laser printing mainly used in offices and for transactional printing (bills, bank documents).
Laser printing is commonly used by direct mail companies to create variable data letters or coupons, for example.
Pad printing
popular for its unique ability to print on complex 3-dimensional surfaces.
Relief print
mainly used for catalogues.
Rotogravure
mainly used for magazines and packaging.
Screen-printing
from T-shirts to floor tiles.
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