What else affects color? The paper’s base color, ink trapping sequence, and drying method all play a role. Color management (color matching) for dark-colored paper is more complex than for white cardstock; using the exact same paper stock during the proofing stage is essential. Final color verification should be conducted under a standard light source.
Why is white ink needed? White ink (opaque white) serves as an underbase: it masks the natural color of dark paperboard, ensuring that the colored graphics printed on top appear accurate. Without this underbase, the paper’s color would “swallow” the printed colors. Essentially, white ink acts as a foundation for the colors.
How are white ink and spot colors handled? White ink can function as a standalone white spot color (e.g., for white text or logos); on transparent materials or dark paper, the white is physically printed on, and the thickness of the ink layer determines the level of whiteness. The goal is to achieve a finish that is sufficiently white and opaque.
A white ink underbase acts as the “foundation” for dark-colored packaging: a sufficiently white base ensures color accuracy. By properly determining the number of underbase passes and the ink layer thickness, even kraft paper boxes can display vibrant, accurate colors.
How is printing done on dark paper? When printing on kraft paper or dark cardstock, a white ink layer is printed first (in one or two passes) followed by the colored inks; the opacity of the white ink determines the final color outcome. To verify opacity, hold the print against the light to check if the base color shows through.
The same design will look completely different when printed on kraft paper versus white cardstock—achieving color accuracy depends largely on whether a white ink underbase is used. This article clearly explains the role of white ink and underbasing in packaging printing, making it easy for clients producing kraft boxes or dark-colored packaging to understand the process.
How many passes of white ink? For dark paper and full-coverage designs, two passes of white ink are typically used: one for the underbase and one to boost whiteness. Costs and production time increase with the number of passes. The decision on the number of passes depends on the paper color and the specific requirements of the design.
