This study introduces a breakthrough in noninvasive brain-monitoring technology through on-scalp-printed and self-drying conductive inks for electroencephalography (EEG). These ultrathin, skin-conformable temporary e-tattoos provide a comfortable and precise way to capture brain activity, overcoming the limitations of traditional EEG systems, such as bulky equipment and manual setup. With personalized sensor layouts, distinct electrode and interconnect inks, and a hair-compatible digital printing process, these on-scalp-formed e-tattoos represent a promising tool for clinical diagnostics, brain-computer interfaces, and wearable health applications.