Cursed Film Canister and Purified Water (Silver Key ritual)

Where the puzzle is

The cursed canister sits on a table behind the blue door on the film school's 1st floor. The cage is in the bathroom of the 2nd-floor apartment, and the moonlit window is in the hotel room behind the door with the red symbol, left of the 2nd-floor elevator.

Sanguis's spell in the Old Book asks for a silver vessel, water from three emerald bowls and moonlight. The emerald bowls are the green save points.

Warning: every save point you drain disappears for the rest of the run. You choose which three. iampanax used the 2nd-floor bedroom, the 3rd-floor office and the 2nd-floor A.S. office; that is just one example, so pick the ones you can most easily live without. The Steam achievement ‘Have You Chosen... Wisely?’ is tied to this step.

Not sure you’re in the right place? Search for your room in Quick find tool.

What you need

• Silver Key: from Sanguis, after you go through all of his SPELL dialogue
• Silver Bottle: the cage in the 2nd-floor apartment bathroom
• Red Pentacle Stone: dropped by Fumus behind the Cow Skull door

Exact spots for each one are on Items and collectibles.

Step by step

1. Wake the canister and talk to Sanguis

   Interact with the film canister on the table, walk away and come back to interact again. Sanguis then shows up in the studio lobby. Pick every SPELL topic until he has nothing left to say; he hands over the Silver Key.

2. Open the cage in the 2nd-floor bathroom

   Take the Silver Key to the bathroom of the 2nd-floor apartment and unlock the cage. Inside is the Silver Bottle.

   

3. Drain three save points

   Use the Silver Bottle on any three save points. Each one you use is removed permanently, so choose with care. After the third, the item becomes Bottle with Three Doses of Water.

4. Open the hotel room with the Red Pentacle Stone

   If you haven't yet, beat Fumus behind the Cow Skull door for the Red Pentacle Stone. Use it on the door with the red symbol to the left of the 2nd-floor elevator.

5. Bless the water in moonlight

   In the hotel room, use the Bottle with Three Doses of Water at the window where the moonlight falls. You get Purified Water.

6. Cleanse the canister

   Go back to the cursed canister and use the Purified Water on it. It turns into Film Canister 3.

If it doesn’t work

Sanguis won't give me the key.

Keep choosing the SPELL options until you have exhausted them all. The key only comes at the end of that conversation.

The hotel-room door left of the 2nd-floor elevator won't open.

It needs the Red Pentacle Stone, which you get by defeating Fumus behind the Cow Skull door.

Can I get a drained save point back?

No. The removal is permanent for that playthrough, which is why it is worth choosing save points you rarely use.

Sources

1. Tenebris Somnia - All Puzzles & Solutions Guide by iampanax Timestamps used: 24:08–27:26
2. Tenebris Somnia Full Game Walkthrough - All 4 Endings [No Commentary] by iampanax Timestamps used: 1:46:54, 1:55:51
3. Tenebris Somnia achievements on Steam (‘Have You Chosen... Wisely?’) by Steam