White ink is liquid, used in inkjet or screen printing; it is laid down wet and cured. White toner is a dry powder used in electrophotographic (laser-style) presses, fused with heat. Both produce opaque white on dark substrates, but the equipment and file workflow differ.
White ink
Common in wide-format inkjet and screen printing. Multiple passes can build opacity. Used for large format, vinyl, and many specialty substrates. File setup is typically spot layer or underbase as the printer specifies.
White toner
Used in digital presses that support a fifth (white) station. Often used for labels, packaging, and short-run applications on dark or clear stock. File setup may be a spot color or specific layer; the press maps it to the white station.
Choosing by application
• Large format, vinyl, signage: usually white ink.
• Sheet-fed dark/clear paper or film: may be white toner or white ink depending on the shop.
• Ask the printer which technology they use and how they want the file.
Common mistake
Assuming white toner and white ink files are identical. RIP and press handling can differ. Send the file format and spot definition the printer specifies for their equipment.