ink is deposited on the support step 217 a corresponds to the end of the traditional process in step 209 b the uv curing silk screen printing ink as described above is spread on the frame by exerting with the doctor blade the pressure required to push it across the die in step 211 b the ink is deposited on the support step 213 b includes the occurrence of the curing step into a uv drying unit the uv rays react with the photoinitiators thus generating the complex radicals or cations which in turn react with the liquid binder achieving the three dimensional crosslinking of monomers and oligomers which leads to the fixing of the solid film in step 215 b the compound alters the structure of the paper fibers which become thinner and take a greater compactness thus generating a transparency effect compared to untreated fibers step 217 b corresponds to the end of the non traditional process and thus to the making of the u201c chemical watermark u201d using the fixative with the above described features a final effect of light variable light and shade is obtained which is very similar to that obtained with the traditional watermarking methods the effect of increased transparency is due to a greater compactness of the fibers which become thinner compared to those not treated just like in the traditional watermarking methods obviously such a method has considerably lower costs than the traditional methods of producing watermarks and therefore it makes it advantageous to use the chemical watermark.