The present invention provides an imaging element comprising on one side of a support a photosensitive layer comprising a silver halide emulsion and an image receiving layer containing physical development nuclei in water permeable relationship with said emulsion layer and on the other side of the support at least one backing layer comprising gelatin and a dye and/or a dye precursor characterized in that said dye or dye precursor is such that after treatment of said imaging element in an alkaline solution with a pH of 10.9 for 20 s at a temperature of 30.degree. C. the backing layer has a reflection spectrum when treated for 20 s at 20.degree. C. in a neutralizing solution with a pH of 7.5 that is visually different from the reflection spectrum when treated for 20 s at 20.degree. C. in a neutralizing solution with a pH of 8.5.