Sorry I'm missing something here. When I do a test signature in a form, the data is saved in the table as:

"data:image/jsignature;base30,4EZ1422341_3R47349g5_3H36744a87l _4DZ34933945b_4X35Z2520Y2453393430Z1655_4JZ2540Y35 310Z224315Y54411_6U0Z3103_3v5e7a4_5T22554476cb6_3U Z33102111320"...