Printing on white shirts is relatively straightforward because the color of the shirt doesn't affect the appearance of the ink. And you will not need a “base layer of white ink”.

Printing on dark shirts requires additional steps and different materials to ensure that the design appears vivid on the darker fabrics. This process is often referred to as "printing with an under base or base color."

Steps for Screen Printing include:

• Preparing the design: setting up the artwork for screens to be created.
• Creating the under base: A white ink base is printed first, serving as a base for the other colors to sit on to ensure their vibrancy.
• Flash curing: After printing the white base color, the ink is partially cured using a flash cure unit, which dries the ink without fully setting it.
• Printing the colors: Once the base layer is flash cured, the colored inks are printed on top. The ink colors should be chosen carefully to ensure they stand out against the dark fabric. If there is “white” in the artwork a Top White ink layer will be printed on top of the base white ink to ensure the brightness of the white.
• Final curing: After printing all the colors, the entire print is fully cured using heat, to ensure the ink adheres properly to the fabric.

The additional steps required for dark shirts are necessary to make certain the colors have a solid foundation to stand out on the dark fabric, resulting in a more visually appealing print. Without a white base color, the ink colors may be muted or may not show up well on the fabric.

Samples of the number of inks used on a white shirt vs a dark shirt: