Since Jon and Gertrude use a tape recorder to store their knowledge, I headcanon that other people connected to The Eye keep track of what they know in different ways.
Sasha James made a video diary once a week about memorable events that happened to her. Sometimes she talked about important things like Martin’s encounter’s with Jane Prentiss, but most the time she just talked about the thing’s she saw in general, like the cafe near her house being busier than usual, or the cool old car that drove down her street. She fed The Eye in the most mundane way…or maybe The Eye was just that entangled with her day to day.
Gerard Keay carried a sketchbook and doodled the small things as they happen, then made full drawing’s of the big events as soon as he got the chance.
Eric Delano carried around a journal and jotted down his thought’s and feeling’s on everything he experienced. It was just meant to untangle his messy thought’s about The Institute, Gertrude, Mary and everything in between, but it ended up feeding The Eye pretty well.
Michael Shelley carried around a camcorder outside of work and would film things some times. He said it was because he had a hobby for film, which was partially true, but he also carried it so he could capture proof if he stumbled across anything like the door that took his friend…
Fiona Law had a photography hobby. She started it as a way to take picture’s of nature, but it quickly escalated into her taking picture’s of anything that felt drawn too. Including: Building’s, animal’s, people, and sometimes even the strange.
Emma Harvey kept a day planner where she would document the results of her “experiments” on her coworker’s day by day. She had a system to write innocuously enough to not draw suspension, like jolting down “Had trouble sleeping,” if Fiona lasted longer than usual before fainting.
Sarah Carpenter would just steal thing’s she thought they were important or interesting. She would keep them in her apartment where they could always be seen under her gaze, feeding The Eye through her occasionally sticky fingers.