At some point in your schooling, maybe even in grade school, you probably did some screen printing. Maybe in art class. Using a frame with a stretched nylon screen, perhaps not as fine a mesh as a stocking, you used a squeegie to force printing ink through a stencil attached to the screen and onto the paper below. It’s a simple process, and essentially the same as commercial silkscreen (also known as screen printing or serigraphy).
Where might you see examples of screen printing?
The screen printing process deposits a thick film of ink on a variety of substrates. You may have seen a portion of text printed right on the wall at a museum to describe the paintings or sculpture in the room. More than likely, this was done via screen printing.
The printed t-shirts you wear (those with thick ink deposits rather than appliques) are another example of screen printing.
Probably the silkscreen you used in school differed from commercial screen printing presses in only a few respects. First of all, it probably only had one screen. When you wanted to change inks to print new portions of your artwork in different colors, you probably had to clean the ink off the screen, remove the stencil that blocked ink from the non-image areas, and then attach a new stencil prior to printing the next color.
A commercial screen printing press, used by online printing companies, can have a single flat bed on which the paper or fabric rests and multiple arms with screens bolted onto them that can be rotated into position to lay down ink onto the t-shirt, convention portfolio, or whatever else you’re printing. This will speed up the printing process significantly.
Also, your school silkscreen probably used a screen made of silk or a synthetic, whereas commercial screen printing presses can use polyester mesh screens or even more durable stainless steel screens.
Photo screen printing provides new options.
Initially, artists either blocked non-image areas of the screen by applying a thick film or painted portions of the screen with block-out solutions to prevent ink flow. Starting about seventy years ago, photography was brought into the screen printing process (think of the pop art posters created by Andy Warhol).
In photo screen printing, the screen is coated with a light sensitive emulsion that is selectively exposed to a light source through a positive image of the artwork (the reverse of the process whereby offset printing plates are burned). The (positive) stencil keeps the light from reaching the image area of the artwork. When the screen is exposed to light, the light source hardens only the non-image areas, allowing the emulsion on the image areas to be easily washed away with water prior to printing. Non-image areas remain blocked out on the screen. With process inks, four screens, and considerable skill, a screen printer can produce full-color photographic images on a wide variety of substrates. Although the thickness of the screen printing inks makes fine-screen halftone work more challenging, the process is evolving.
When should you choose screen printing?
There are a few major reasons to choose screen printing.
First among these is the ability to print on unusual surfaces such as walls and garments. This is in part because screen printing does not require the intense pressure of offset lithography, so you can print on surfaces that are not flat. You can even print on mugs, pens, and such, depending on the flexibility of the screen and your creativity in devising holders for the objects.
Set-up (make-ready) operations for screen printing are involved and lengthy, however, adding to the cost of the process. Therefore, screen printing is your best choice for longer press runs. For shorter press runs, digital printing processes such as inkjet printing are coming into use (even for items that are rounded, such as pens or mugs), depending on the ingenuity of the printer in developing carriers to hold the items motionless under the inkjet nozzles.
You may not have realized this, but…
Here are some uses for screen printing, some of which you may never have imagined:
- Electronic printed circuit boards
- Medical devices
- Glass, wood, metal, and plastic items
- Clocks and clock faces
- Snowboard graphics
As you cherry-pick your team of digital printing companies, it’s a wise decision to include a quality screen printing shop in the mix.
This entry was posted
on Wednesday, August 10th, 2011 at 12:25 pm and is filed under Printing, Screen Printing.
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