Refer to the descriptions and video(s) below on how to find all items that you can inspect in the game. You don't need to reach the next checkpoint to save your progress. As long as you inspected the item, you can immediately quit to the main menu without finishing the checkpoint or chapter. These are divided to individual checkpoints per chapter for your convenience, in case you need to do some backtracking for anything you missed.
Checkpoint: A Path Seldom Walked
1. Newspaper #10
After the cutscene when starting the chapter, go downstairs to the firs troom. The newspaper is found just ahead, near the corner of the room.
2. Document #16
After reading the newspaper, continue along the main path until you reach the only door to the left that you need to open. Turn to the left and find this document on top of a crate.
3. Phonograph Cylinder #16: The Anarchists 29.11.86
After encountering a large group of enemies in the tunnel and clearing it, continue to the tunne to the left. The path will split to the two; take the one to the left to find a chest in the dead end.
Checkpoint: Time is Running Out
4. Photograph #11
As soon as you reload this chapter, just walk a bit until you reach a barricaded doorway. To the right is a crate where you'll find the last photograph on top of it.
Congratulations for finding them all!