Custom Printing Process – Screen Printing

A custom screen-printed paper bag, box, or wrapping paper roll is a great way to raise brand awareness. The process itself is also relatively simple so you get your custom packaging quickly. But how, exactly, does it work? We’ve taken a look at screen printing (also known as silk printing or serigraphy) and how we use it to create custom packaging for business.

Types of Screen Printing

The basic definition of screen printing is forcing ink (or metal) onto a surface through a mesh screen/stencil to create a pattern, picture, or text. However, there are a few types, which are mainly identified by the ink being used. Here are the most common inks for screen printing and why you might use them.

• Plastisol – An ink where PVC particles are suspended in a chemical additive called a plasticizer. This additive increases the flexibility of the ink for printing. This ink is known for its image quality but has a plastic look (which is just fine for plastic bags).
• Discharge Inks – These inks either lighten or darken the dyes that are already in a material, making them good for colored packaging.
• Water-Based Ink – These are used when the printer wants a softer, more natural look. They also penetrate materials deeper than plastisol-based ink.
• Flocking – This process actually doesn’t involve ink at all. Instead, an image is created by applying glue followed by foil that gives it a shiny appearance.

Screen Printing Process Step by Step

Regardless of your ink choice, the screen printing fundamentals remain the same. Here is the 7-step process when using a screen printing machine:

1. Print the design onto a transparent acetate film sheet.
2. Select a mesh screen that suits the design and material texture and coat it with a light-reactive emulsion layer.
3. Lay the acetate sheet onto the screen and expose it to bright light. This will harden the exposed emulsion while leaving the substance in the covered area as a liquid. (Note: a separate screen must be used for each ink color in the design.)
4. Carefully wash off the remaining liquid and dry it to complete the stencil.
5. Add the screen to the printing press and lay the item flat on the printing board beneath it.
6. Lower the stencil onto the item, add ink to the top end of the screen and use a squeegee to pull the ink along the screen and press it through the stencil. Repeat for each item being printed.
7. Use a dryer to cure the ink and double-check that the design looks correct.

Digital Printing and Block Printing

People often bring up these two printing methods when asking about custom items. We’ve taken a brief look at how they compare to screen printing.

What is Digital Printing?

Digital printing is essentially a newer version of screen printing. Both involve applying ink directly to an item, but for digital printing, the design is processed by a computer. It allows for more detail, but the colors aren’t as bright, and it’s harder to print on uneven surfaces.

What is Block Printing?

If digital printing is screen printing’s successor, then block printing is its forefather. One carves a design into a block of material such as rubber or linoleum, covers it in ink and presses the design onto the item. The results are typically bolder but have less detail unless the carver is very skilled.