Understanding how inks lay down on different substrates is beneficial knowledge when it comes to certain applications. It helps determine where and how to use white and clear inks in an image.
CMYK inks normally print with a matte finish. When an image is printed on a metallic substrate, lighter areas allow more of the metal or mirror finish to show through. White ink can be used to accent highlights, provide a base for printing skintones or add visual solidity to areas in the image.
However, the matte finish dulls the metallic sheen. That’s when clear ink can help. It will make CMYK inks appear translucent, giving the color those cool metallic properties. It can be applied as an all-over flood coat or as a spot to highlight areas in an image. Any areas with white ink underneath will appear glossy.
A good design rule to remember: white-under and clear ink areas will visually pop forward.
On clear materials, CMYK inks appear frosted. This is useful for privacy window film applications. For a more in-depth look, read our previous blog on creating dynamic window graphics.
For backlit applications, frosted areas without white ink lets more light through. In the example below, the image was printed CMYK > white ink > CMYK. However, white ink was omitted around the lights. All “open” areas in the image (0% CMYK) were filled with a C=5, M=3, Y=3, K=2 color break. This frosts the clear material, dispersing the light. As a result, the lights around the model’s neck look more realistic when backlit.
One popular use of clear ink is to emphasize subject matter that is naturally glossy.
Pro tip: Use a channel in the image to create the clear ink spot channel for a more natural effect. In the below example, the green channel was used to create the spot clear channel. The levels of clear ink will vary across the handbag, eliminating a hard gloss edge.
Check out our Applications that WOW! resources page to learn how to perfect EFI’s backlit multi-layer printing techniques and more advanced applications. You’ll find video tutorials, application tech tips, and the must-have Ultimate Guide to White, Clear and Multi-layer Applications.
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