The ABCs of Screenprinting

Legend has it that a contemporary admirer of Michelangelo's work with marble stated a question to the effect of: "how do you make such a beautiful statue out of a piece of marble?" Reportedly,Michelangelo answered to the effect of, "It's easy. I just take away the parts of marble that don't belong there."
Fast forward a number of centuries and reduce a dimension to 2-D. This would classically describe what a craftsman does in silk screening. At the very base of the model a craftsman takes a frame and catches a fine mesh typically made of a synthetic material. This mesh encased frame has attached with a pattern utilizing a thin-film material preventing Ink from passing through the mesh. Therefore, anywhere the thin-film is not the ink may pass through to the target material.
At a high-level, this explains the silkscreen printing process. If that was all there was to it, anyone with an eye for art could wield an X-Acto knife in the thin-film to create a pretty pattern.
Screen printing was first discovered in China around about 1000 AD. It didn't gain any real traction until the 18th century in Europe when silk became more available. Silk is strong yet can be very thin. That is probably why it is often referred to as silk screening. In the USA, it became popular in art circles when Andy Warhol created hit depiction of Marilyn Monroe.
I suspect the saying, "the devil is in the details" may well have been first uttered by a silkscreen printer. The bedeviling points come from the sheer number of options in classical silkscreen printing. As you may have seen in other articles here, 'Ink' very vague and nebulous term. We have already reviewed 'ink' run through an HP printer to 'print' replacement human bones. That research has successfully grown human kidney by printing with human cells. Considering this, it is little wonder that the 'ink' used in silkscreen printing can and does vary wildly.
For example I have a heavy cotton black sweatshirt. The 'ink' is specialized in several ways. The pigment had some sort of material that expanded when heated. This gave the graphics a 3-D relief. Further, the visible light pigments had a chemical added at the time of manufacture so the graphic would absorb light, and 'glow-in-the-dark'. The graphic is some frogs. Trust me, it really amazes a child under the age of five to see 3-D glowing frogs on my sweatshirt ;).
Screen printing has a lot more to do with our daily lives than clothing and curtains. Everything from the balloons to billboards, decals to medical devices use screen printing. Even circuit boards, and solar cells are created in this fashion.
Today, we're beginning to see actual electronic circuits that are printed in this fashion.
Whether it be an old-fashioned flat screen, a cylinder or a rotary press, these are often analog methodologies. Generally speaking, an analog technique is more expensive to set up, with a great return on investment. If you are doing a larger number of units. Let's contrast this to digital screen-printing.
In digital screen-printing, we can go back to our old friends the Pizeo-electric way as created by HP, or the bubble jet method with Canon as the creator.
Because the pigment must go through a print head, it cannot pack the density the analog methods can. If one was to want to print on the aforementioned black sweatshirt, it would require laying down a white base before the colored pigments.
You are carrying a serious advantage when doing digital screen printing for: prototyping, one offs and short runs. More than a couple of entrepreneurs have made the 10K to $200,000 investment to print, direct to garment. You can find them at carnivals, kiosk's in malls, or small retail storefronts. 

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