Though wax-resin relining produces excellent results in the normal case, there are exceptions where the texture of the relining canvas may be faintly visible after relining. Such cases usually occur with paintings on particularly finely-woven canvas of poor quality (end of the nineteenth century, mainly Impressionists). Someline is a thin synthetic fabric (acrylic and nylon, thickness 20-500 microns) composed of long fibres felted together. It is placed between the old and the relining canvas.