Tray process the film, as you would paper, but half-way through the correct development time transfer the developer tray to your enlarger baseboard. Finish developing the film and continue processing as normal. After the film has dried, expose it by contact print or enlargement on your favorite bromide paper. The length of the fogging exposure in relation to the image exposure directly affects the solarization. Short initial exposure and long fog exposure will give results similar to a negative.
Color images are inherently low in contrast and difficult to solarize.
Colors wash out and results are unpredictable even when using a pre-solarized negative as explained above.