Zinc is highly transparent white but most of the paint manufactures add it to titanium. The manufacturers say zinc makes the paint warmer and more like lead white. So they add zinc to titanium for the buyer's own good. (I suspect zinc is cheaper than titanium...at least you need to use twice as much for the same coverage.) Plus zinc is not archival in oil paint and will eventually cause the oil painting to fail.
So I bought some lead white from Kama Pigments. Kama is a Montreal paint manufacturer that makes artist quality oil paint in small batches. Very nice! And a great place to buy pure pigments and archival mediums and supplies.
Sorry, I wanted to add the before painting but couldn't find it.