To be frank, titanium dioxide will always be less transparent than a possible dispersion of zinc oxide. This partially relates to particle size. Titanium dioxide has gotten more transparent as suppliers have made the particles smaller. The downside of a smaller particle size is that it shifts protection from short wave UVA to be predominantly UVB. For this reason, you should never use a mineral sunscreen that exclusively uses titanium dioxide as its active UV filter. It will not have any protection in the long wave UVA and would not be considered truly broad spectrum. Transparency also relates to a scientific phenomenon called Index Matching where you match the Refractive Index of the particle in the carrier you are dispersing it into. Titanium Dioxide has a higher refractive index and is harder to match. We’ve found a supplier of zinc oxide that expertly matches the refractive index of the carrier (medium chain triglycerides) and this helps to make our sunscreens as transparent as they are.