Lamps, placement limits & the elevator
Place lamps to reveal more of the cavern. When the number you can place is the limit, inspect the elevator upgrade: the developer explicitly links elevator upgrades to additional lamps. Holding an unplaced lantern no longer reveals unexplored geography in v0.4.3.5.
Out of lamps: which upgrade should you inspect?
Open the upgrade tree and look at the elevator option when lamp capacity blocks expansion. The large-level update makes that relationship explicit. Adding a miner hiring sign changes a different capacity; see the upgrade comparison if those limits are being confused.
The five-per-trip elevator limit in the v0.4.3.5 patch is not a five-lamp cap. Read the placement allowance in your current build instead of using the passenger number as a lamp count.
Place the lamp before relying on its light
Move the placement preview to your intended location and use the game’s placement feedback before confirming it. Once placed, inspect the newly visible area. This is the point at which to check routes and enemies; do not use a carried, unplaced lantern as a scouting tool.
The current patch specifically stops held-lantern geography scouting. An older recording using that trick describes different behavior. The patch does not establish an exact lamp radius or guarantee that a newly lit area is safe.
A lamp can also affect Lure Brew reach
The developer’s Lure Brew range reply says a lamp must be close enough to the target to place the potion. The brew cannot simply be dropped into a locked area. Use the Lure Brew targeting guide for the specific clown cue and placement checks.
What light does not prove
A lit route is visible, but visibility alone does not prove a spawn-suppression radius, permanent safety, or a particular enemy response. This page does not have verified durability or distance measurements. For a worker that will not use a visible route, check the target marker and blocked-ore symptoms rather than assuming darkness is always the cause.