Playing D&D 5E we ran into a problem concerning our Rogue. With normal vision he seemed useless in scouting caves ahead. Trying to fix this by using Lamps and candles strikes me as problematic as this must influence his stealth checks (in a negative) or the Monsters perception (in a positive way). How can we use his stealthy skills while mainting the amount of lighting?
Yes, using a light in darkness makes a sneaking rogue obvious to monsters
...provided that the monsters can see. The DMG is pretty emphatic about this on page 105 (the section on Darkness and Light in Dungeons):
The light of a torch or lantern helps a character see over a short distance, but other creatures can see that light source from far away. Bright light in an environment of total darkness can be visible for miles, though a clear line of sight over such a distance is rare underground. Even so, adventurers using light sources in a dungeon often attract monsters...
I am assuming that the rogue is holding the light source to use it to light his path, so the light is shining on him - illuminating him for all to see.
Note that the errata to the PHB corrects heavy obscurement so that vision works in it as you would expect:
A heavily obscured area doesn’t blind you, but you are effectively blinded when you try to see something obscured by it.
This means that a monster standing in darkness can see through the heavy obscurement from the darkness to the brightly lit rogue. Unless the monster is distracted or looking the wrong way, it will see the rogue. Of course in combat it will see the rogue automatically as all combatants are deemed to be aware of all other combatants.
Yes, if the monsters can see the light.
In plain sight, it will be obvious that monsters are going to see him.
However, remember that any source of light has a bright radius and a dim radius. So if you are at an angle of a corridor and the light doesn't touch the side the monsters see, he won't be detected. Your player could also use some kind of Clamshell to quickly hide the light when needed.
If the monsters cannot see the light
Behind a door for example, you still have to make a stealth check for the noise coverage!
The mechanics of hiding are discussed at length in What advantages does hiding have?. The most relevant rules are:
You can’t hide from a creature that can see you (PHB p.177)
Passive Perception. When you hide, there’s a chance someone will notice you even if they aren't searching. To determine whether such a creature notices you, the DM compares your Dexterity (Stealth) check with that creature’s passive Wisdom (Perception) score, which equals 10 + the creature’s Wisdom modifier, as well as any other bonuses or penalties. If the creature has advantage, add 5. For disadvantage, subtract 5.
The DM decides when circumstances are appropriate for hiding. Also, the question isn't whether a creature can see you when you are hiding. The question is whether it can see you clearly. (PHB errata)
Being able to Hide requires that you are not seen, remaining hidden requires that you not be found. So, holding a torch in someone's line of sight will prohibit you hiding in the first place but it will not mean that you are automatically found. It would be fair to say that trying to hide in the dark holding a light source merits disadvantage on the check but it shouldn't preclude it.
Your Dexterity (Stealth) represents natural talent (your Dexterity modifier), your training (your proficiency modifier) and a huge slice of luck (a d20 roll) - in narrative this could mean that you keep the light source behind your back, pick exactly the right moments to move and have a guard who is drunk, asleep, taking a dump or otherwise distracted.
The simplest answer would be to cast Darkvision on the Rogue before he scouts ahead. Of course, Darkvision is a 2nd level spell, so the Wizard needs to be at least 3rd level, and it is a resource heavy spell until the party is advanced enough to create magic items... assuming the DM in this campaign allows item creation. If not, I'd suggest the DM include some sort of wand of Darkvision or something similar in a loot-drop just to make this problem mostly go away... although the occasional wand is out of uses twist would make for a fun evening.
This question has two answers, based on two unique cases:
Your Rogue is trying to hide from Creatures with Darkvision:
Creatures with darkvision see in dim light as if it were bright light, and darkness as if it were dim light. Therefore, even in pitch black, they do not suffer from the blinded condition. They have disadvantage on perception checks, but they are still capable of seeing.
However, if your Rogue is carrying the light openly, then they are in a region of bright light. If they are partially shading it, they may be in dim light, but unless they completely cover it, they are not in darkness.
So within a creatures darkvision range, the creatures will not have disadvantage on perception checks to see the rogue. DMs should give advantage on perception checks and/or disadvantage on stealth checks as they see fit, recognizing that light sources are visible beyond their illuminated range, provided there is no obstructions blocking their view.
However, if the rogue is behind cover, the light source may not be visible. The DM should adjudicate this situation based on the surrounding terrain and the likelihood that the light could reflect off of surrounding terrain (trees, cave or building walls/ceiling, etc...) and be seen.
If the Rogue is outside a creatures darkvision range, apply the (below) case where the creature does not have darkvision.
The Rogue is trying to hide from Creatures without Darkvision:
If creatures are in the dark and do not have darkvision, they suffer from the blinded condition, meaning all visual perception checks automatically fail. Thus, RAW, they should not be able to see the Rogue.
However, this seems to present a situation where a creature with darkvision, 1 ft can see any object light by bright light, but a creature without darkvision cannot see the same object. A more RAI (IMO) is to say that creatures are blinded towards anything in darkness.
This means that if your Rogue is carrying the light openly, then they are in a region of bright light, and they will be spotted. If the Rogue shades the light, so that it only illuminates the ground just in front of them, then other creatures will have disadvantage on perception checks to spot them. Again, judicial adjudication of interaction with cover is required by the DM.
TL;DR: Your rogue will be visible if the only thing they were hiding in is the darkenss, and they illuminate that darkness with a light spell.
PHB pg 177
You can't hide from a creature that can see you.
What Can You See? One of the main factors in determining whether you can find a hidden creature or object is how well you can see in an area, which might be lightly or heavily obscured, as explained in chapter 8.
PHB pg 183
VISION AND LIGHT
A given area might be lightly or heavily obscured. In a lightly obscured area, such as dim light, patchy fog, or moderate foliage, creatures have disadvantage on Wisdom (Perception) cheeks that rely on sight. A heavily obscured area-such as darkness, opaque fog, or dense foliage-blocks vision entirety. A creature in a heavily obscured area effectively suffers from the blinded condition (see appendix A).
The presence or absence of light in an environment creates three categories of illumination: bright light, dim light, and darkness.
Bright light lets most creatures see normally. Even gloomy days provide bright light, as do torches, lanterns, fires, and other sources of illumination within a specific radius.
PHB pg 290
- A blinded creature can't see and automatically fails any ability check that requires sight.
PHB pg 173
The DM can also decide that circumstances influence a roll in one direction or the other and grant advantage or impose disadvantage as a result.
PHB pg 183-185
Many creatures in the worlds of D&D, especially those that dwell underground. have darkvision. Within a specified range, a creature with darkvision can see in darkness as if the darkness were dim light, so areas of darkness are only lightly obscured as far as that creature is concerned. However, the creature can't discern color in darkness, only shades of gray.