Identification studies on biometric signatures have entered the subject area of scribal expertise in earnest for several years. The article presents theoretical possibilities for further expanding the field of biometric signatures, for example, to documents executed in notary offices or private wills drawn up on mobile devices equipped with an application that records the biometric parameters of the signatures made on these documents. While the examination of signatures from notarial documents should not pose significant research problems, they may arise in the case of wills, especially when there is suspicion that the signature was made with a so-called supported or guided hand.
From the experiments carried out by the authors of the article, it can be seen that the features of the biometric signature made:
hand supported with coincident graphometric parameters with authentic signatures of the tester have compatible biometric parameters characterizing these signatures;
hand guided at coincident or different from the original signatures of the tester have distinctly different biometric parameters characterizing these signatures.
It was also observed that the parameters of the biometric signature made by the guided hand are analogous to the biometric characteristics of the comparative signatures made by the forger in the name of the tester. The results of the experiment also made it possible to verify the phenomena hitherto operating in classical handwriting expertise describing signatures made by the guided and supported hand executed on a paper substrate.