However, it seems like it is not the case, meaning that Journal pages work as an additional drop, much like Antiquarian relics, so another item is very unlikely to take its place.

It is worth to mention that any other loot in table, where pages are, has more chance of showing up thus effectively reducing chance of journal page if other loot and pages have same priority. If they have no priority than the base chance of 1/2000 is seriously lowered because any type of loot can take its place. It is unknown whether journal pages have priority over other loot or not.

Light influences chances by giving 1 chance of modified 1/2000 to all lootable curios:

Barnacle Crusted Chest (Shovel): 3 chances at 1/2000.

Lost Luggage (Key or Antivenom) 3 chances at 1/2000.

Old Tree (Antivenom): 3 chances at 1/2000.

Pile of Bones (Holy Water): 2 chances at 1/2000.

Iron Maiden (Medicinal Herbs): 2 chances at 1/2000.

Locked Strongbox (Key): 3 chances at 1/2000.

Unlocked Strongbox: 75% of 2 chances at 1/2000.

The higher the light value, the lower the chance is of finding one. They can only be found within certain curios when not influenced by torchlight. The probability is influenced by torchlight in a way that allows one extra chance of 1/2000. The journal pages are very rare with the base probability of finding one is is 1/2000 (0.0005).

7 A strange note, written on bloody human flesh.

5.6 Blood Soaked Pages Torn From A Journal 6/6.

5.5 Blood Soaked Pages Torn From A Journal 5/6.

5.4 Blood Soaked Pages Torn From A Journal 4/6.

5.3 Blood Soaked Pages Torn From A Journal 3/6.

5.2 Blood Soaked Pages Torn From A Journal 2/6.5.1 Blood Soaked Pages Torn From A Journal 1/6.5 Blood Soaked Pages Torn From A Journal.

Reddit journal page darkest dungeon