“With White Ink” can mean one of two things.
It can mean your design includes white elements that need to be printed.
Or, even if your design does not include white, it can mean adding a white ink base layer underneath the design.
On clear or dark backgrounds, white ink helps colors look more vibrant, solid, and true to the original design.
For production, the minimum line width for white ink is 0.2 mm. This means very fine lines or very small text may not be suitable for white ink.