All you need to know about silk printing

All you need to know about silk printing
Container and Packaging
by Container and Packaging
September 8, 2020, Updated June 16, 2021

Silk printing is the process we use to print directly on a bottle. It is an industrial process that involves many steps, a lot of machinery, some artistry, and a little bit of elbow grease.

At parties and other social gatherings most people gather around and show off … Katie can fit her fist in her mouth, Laina can sound like a bag pipe, and Sara has false teeth–the result of an unfortunate biking accident when she was six. I grew up printing. I grew up creating packaging artwork. With all humility, I submit, I know what I’m talking about when it comes to this process. Take THAT Katie, Laina and Sarah.

Most silk print jobs go through this process:

Art.To print a bottle, you’ve got to have art. Art (or artwork) is typically a digital rendering of what you want on the bottle. It is designed at 100% scale and can have 1-2 colors (we’ll do a third color if you really twist our arms and want to pay for it). It’s typically designed using professional design software like (my favorites) AdobePhotoshop, Illustrator, orInDesign. Word, Excel, or Paint, don’t cut it. You can hire a professional artist to help you get your artwork ready (hint hint, 1-800-473-4144). Here’s an example of some artwork for the fictional Le Fleur French SilkTexturizing Treatment. This is a two color silk print project (orange and brown):

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Films. Once you’ve created your digital artwork, you then need to create film positives. This is done by printing your artwork out on transparent sheets of plastic (think overhead projector transparencies). There’s a big difference between film positives and film negatives. For silk prints, we need film POSITIVES.

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Regardless of the color that you want printed (in our example, orange and brown) the artwork is converted to black, and then printed on transparent sheets. Because we have two colors, we need two films; one for the orange and one for the brown. See how the artwork is separated into two films?

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Screens. Once the films are made, we then need to “burn” the image of your art into the screen. A screen is a piece of ultra-fine mesh silk fabric stretched over a frame. The silk is coated with a light-sensitive water-soluble glue or emulsion that is then air-dried. The film is laid on top of this glue-coated silk and then exposed to a high-power UV light. The film positive (the black printed part) blocks the light and prevents the glue from curing. The screen is then washed with water and the uncured glue is washed out, leaving your artwork “burned into the silk.”

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Ink will pass through all of the bare silk areas. The dark orange color is where the ink is blocked. See how we’ve made the film positive into a negative?

Ink. Inks are mixed to match the colors that you specify in your artwork. Many print shops use the PANTONE MATCHING SYSTEM (see my post about Lawrence Pantone).

Printing. So we’ve created the art, we’ve made films out of that art, and then we’ve burned that art into a screen. The screen is then fixed to the print machine and the printing begins. A bottle is placed in the machine, the machine is activated, the bottle is raised to the underside of the screen and then a squeegee presses the ink through the screen onto the bottle while the bottle rotates. The ink is then dried and VOILA, the print process is done.