Titanium dioxide

Titanium dioxide is a white mineral pigment used in soap making to brighten a bar's overall color, create true white sections for swirls and layers, or lighten and soften other colorants that would otherwise look too intense or dark on their own.

Like mica, it is typically dispersed in a small amount of light oil before being added to batter, which helps it blend in evenly instead of leaving white streaks or specks. It is used in both melt and pour and cold process soap, and only a small amount is needed to noticeably brighten a batch.

When buying it for soap, look for a cosmetic-grade product intended for skin use rather than an art-supply or ceramics-grade powder, since purity and particle size can differ between grades. A common mistake is adding undispersed powder directly at trace, which tends to leave visible white flecks scattered through the bar, or using far more than needed, which can make a bar chalky and flat looking rather than simply brighter and cleaner.