It’s basically a question of impact and strength. Titanium White is made with the titanium dioxide pigment and is the brightest and most commonly found white on the the artists’ palette. It has a high opacity level and a clean, blue toned appearance. It’s an excellent choice for making tints but it can be too strong – so use it cautiously as it can dominate colors. On the other hand Transparent Mixing White is made with zinc oxide, a highly transparent pigment with a tenth of the tinting strength of Titanium White. It’s weakness makes it perfect for subtle lightening, particularly in combination with other transparent colors. Use it to create softer – less pastel – effects.