DARQ: Complete Edition

In chapter 6, when you get to the hallway where there is a room to your left with the plague doctor / bird man that you have to sneak past to get the key, go up the wall to the right and onto the ceiling. Sneak into the room above the bird man and it will lead to a hole above him that contains the journal.

If you are going back and collecting any journals you missed with chapter select, you do not have to finish the level to save it. You can immediately quit to the menu / choose a new chapter after picking it up.