Building a white layer in your file is a requirement for printing on clear or metallic substrates to ensure opaqueness of ink on clear substrates and to create contrast between non-metallic and metallic images and text on polychrome materials such as silver metallic or holographic film. A white layer provides the bright, consistent “canvas” necessary for CMYK inks to display their full vibrancy and opacity, just as they would on regular white material.
Setting Up a White Layer in Adobe Illustrator®
1. Set Up Your Document
- Color Mode: Go to File > Document Color Mode and ensure it is set to CMYK.
- Vectorize Art: Ensure all elements intended for the white layer are vector objects (paths or shapes), not raster images.
2. Create a Spot Colour Swatch – Since white ink won’t show up on white digital “paper,” you must create a custom “Spot Colour” so the printing press can identify it.
- Open the Swatches Panel (Window > Swatches).
- Click the New Swatch icon.
- Swatch Name: Name it exactly as your printer requires (common names: White, Spot_White, or HPI-White).
- Colour Type: Change this to Spot Colour.
- Colour Build: Choose a colour that contrasts with your art file colours (perhaps light cyan or light pink) so you can see where the white ink will be applied. (This colour will not print; it is just a digital placeholder.)
3. Create the White Layer
- Open the Layers Panel (Window > Layers) and click the Create New Layer icon.
- Name the layer “White Ink” or “Spot White”.
- Copy and Paste in Place: Select the artwork you want to be white from your original layer, copy it (Ctrl+C), and use Edit > Paste in Place (Ctrl+Shift+V) onto your new White Ink layer.
- Apply your new Spot Colour Swatch to these elements.
4. Enable Overprinting
- This ensures the white ink prints underneath or alongside your colors rather than cutting a hole (knocking out) through them.
- Select all objects on your White Ink layer.
- Open the Attributes Panel (Window > Attributes).
- Check the Overprint Fill (and/or Overprint Stroke) box.
- To verify, go to View > Overprint Preview to see how the layers stack