Image forming process, ink set, image by ink-jet recording, recorded article, surface-treated article and surface treating process

An image forming method comprises a step of reacting an ink containing a coloring material with a liquid composition containing fine particles reactive to the coloring material on a recording medium, where the reaction between the coloring material and the fine particles occurs in a liquid, the coloring material is adsorbed on the surfaces of the fine particles while keeping the monomolecular state as in the ink, and the fine particles having the coloring material on the surface aggregate each other. This method can provide images of high optical density and high color saturation, with less occurrence of white stripes in the image.