An image forming system includes an image forming apparatus, a fixing device, a varnish image forming apparatus, an image reading portion, and a controller. The controller corrects first image data depending on first detection image data on a toner image formed on a first recording material and read by the image reading portion, and then depending on the corrected first image data, a toner image is formed on a second recording material subsequent to the first recording material. The controller corrects second image data depending on second detection image data on a varnish image read by the image reading portion, and then depending on the corrected second image data, a varnish image is formed on the second recording material.