In accordance with the present invention, a colloidal immersion lithography medium is provided. The medium comprises: a) a continuous liquid phase comprising a liquid having an index of refraction of at least 1.0, generally 1.4; and b) a plurality of particles having an average particle size between 1 nanometer and 2 microns and having an index of refraction of at least that of the liquid, substantially homogeneously dispersed in the liquid phase. Also provided are methods of preparing a colloidal immersion lithography medium, immersion lithography systems, and immersion lithography processes.