There is an opaque white ink, but it is used as an undercoat to mute the paper color so it won’t affect the perception of the ink color.
It can be hard to keep reversed type readable. The delicate, hairline serifs on some typefaces can be filled in by a spread of the surrounding ink, as can type in a small point size. To keep reversed type readable, follow these guidelines:
- Fonts: Use sans serif fonts or make serif fonts bold.
- Point size: Avoid small point sizes, especially if using a serif typeface.
- Spacing: Increase the leading (the space between lines) and the kerning (the space between letters).
- Contrast: Ensure adequate contrast between the text and the background it is reversed out of. White type reversed out of a light blue background will be much harder to read than if reversed out of a dark blue background.
- Reversed type attracts attention, so use it sparingly.