An anodized niobium (Nb₂O₅) layer on a niobium (Nb) plate makes various colors. A driving force of the coloration is considered to be the thin film interference between the Nb₂O₅ layer and the Nb plate. In this study, we explore the possibility that a toner mask method could be used for preparing a digital image on the Nb plate by an anodization. And we tried to erase the image on the Nb plate. We found that 1% hydrofluoric acid solution is able to erase the image, although a ghost image appeared. We also explored how to prevent the ghost image appearance.