I recall hearing about a procedure to increase contrast and/or color saturation when making color prints, but unfortunately I can't find a reference to it. The procedure involved, from memory, dunking a (partially?) processed print in some extra chemistry and then repeating the development. Sorry I can't be of more help. I'm just posting this so you can try looking for more information. Maybe a Web search on keywords like "increasing color contrast film" would turn up more information.