Transfer paper for outputting color images, suitable for use as a transfer member used in a color electrophotographic apparatus capable of forming a multi-color toner image by using at least two colors of single-color toner. The paper has a whiteness degree of 85% or more and an opaqueness degree of 90% or more. A method of forming a color image includes the steps of transferring a color toner image to transfer paper having a whiteness degree of 85% or more and an opaqueness degree of 90% or more, and heatingly fixing the color toner image.