in the faq it states ...
Darkness: Can adding additional sunrods to the area of the spell (Core Rulebook page 263) )increase the light level?No, sunrods can never increase the light level of an area of darkness because they are not magical sources of light. In such an area, it automatically defaults to the ambient natural light level, and then reduces it one step.
—Jason Bulmahn, 10/21/10
what this says to me (and I just want to make sure) is that
: if underground where the only source of light is a torch (or other piece of equipment), when darkness is cast, the natural light goes back to darkness and then goes a step down (if thats possible) with the darkness spell.
: if underground and the only source of light is a light spell, when darkness is cast, the natural light is from the light spell and thus drops it to dim.
Is this right?
I read "ambient natural light" to be what would be present without any 'artificial' light sources i.e. torches, sunrods, light spells, etc. So, the normal light level for underground is total darkness.
So, darkness would indeed cancel the light spell and the area would be in total darkness.
I read "ambient natural light" to be what would be present without any 'artificial' light sources i.e. torches, sunrods, light spells, etc. So, the normal light level for underground is total darkness.
So, darkness would indeed cancel the light spell and the area would be in total darkness.
While this interpretation is the most common, and a very simple one (and as such may be sufficient for most gamers, who should feel free to stop reading and carry on with whatever else they were doing), the actual visibility and light rules that Paizo has published seem to me to be substantially more complex and robust than this.
While the interpretation I'm about to present is not simple, it does address the robust mechanics of Paizo's Vision and Light rules, and how various bits of magic interact with them. (It should be noted that the old 3.5 Vision and Light rules were similar in presentation but vastly different and very poorly defined in application, and as such, the Pathfinder rules are a dramatic improvement both in terms of robust application and in terms of making stuff clear and useful.)
Vision and Light: (http://www.d20pfsrd.com/gamemastering/exploration-movement#TOC-Vision-and-L ight)
The keys to understanding the functionality of this system is the recognition of a well-defined scale of lighting levels (Bright light, Normal light, Dim light, No light (darkness), and Supernatural darkness*) and that ALL light sources are now defined as having TWO radii in which they produce slightly different lighting effects.
The radius listed in the table (accompanying the Vision and Light rules) as the Normal radius is the radius of primary illumination - in all table entries except where explicitly noted, this is a "lit radius" of normal light. The measure listed in the table under the column heading "Increased" defines an area outside the lit radius in which the light level is increased by one step (on the given scale of lighting levels), in effect defining a doughnut-shaped zone of secondary illumination outside the central zone of primary illumination.
In cases of overlapping areas of primary illumination, the strongest source providing primary illumination determines the base light level within its radius, with any non-overlapping regions deriving their base lighting level from their source of primary illumination.
Once the base light level is determined for a lit area, any light sources that generate areas of secondary illumination (as most do) that overlap other areas of secondary illumination or the primary area of illumination may cause the light level in the areas their secondary illumination zones overlap with to increase by one step. This is determined by the description for the various applicable source item(s) or effect(s), for example, torches and sunrods do not increase the light level in areas of Normal light or Bright light.
So far, so good. Lighting effects are well-defined and complex, but manageable to administer, as almost all sources of light indicate the conditions under which their secondary areas increase the light level.
Now we come to the magical bit about light (and darkness (the spell, now))...
Most Core spell effects that bear the [light] descriptor have clearly defined primary and secondary areas. The darkness spell, however, is worded in a nonstandard fashion. The initial statement, that the spell "causes the illumination level in the area to drop one step, from bright light to normal light, from normal light to dim light, or from dim light to darkness," is very clear, and easy enough to deal with as it interacts with the existing system so far. The secondary statement in the spell is what gives everyone kittens, however: "Nonmagical sources of light, such as torches and lanterns, do not increase the light level in an area of darkness. Magical light sources only increase the light level in an area if they are of a higher spell level than darkness."
The key word is increase, which is important due to the easily misunderstood use of it here in a technical mode as opposed to in a descriptive-flavor mode. Inasmuch as all light sources defined in the core rules have mechanics defining an area in which they increase the light level, and the use of the word increase is consistent, to the point of being the heading of the column in the table for Vision and Light, increase is used here in that same sense, and not in the more general (less technical) sense that lighting a torch in a dark room increases the lighting level in the room or a deposit into your savings account increases the balance in the account. Both of these remarks are true, but neither is germane to the technical mechanics of the darkness spell.
The latter statement in the darkness spell indicates that secondary areas of illumination generated by any nonmagical effect or source, or by any magical effect of equal or lower spell level than the spell level of the darkness effect, are negated within the area affected by the darkness spell. Areas of primary illumination, however, being described in the absence of the technically-defined notion of increasing illumination (in that they directly illuminate a given area), continue to directly illuminate their given areas, with such illumination being subsequently diminished by one step by the effects of the darkness spell, as described in the initial statement of darkness.
Thus, a darkness effect centered 20' away from a torch in an otherwise dark area will cause the area of overlap between the torch's area of primary illumination and the darkness effect to be lit with Dim light, the area of overlap between the darkness effect and the torch's area of secondary illumination to be dark, and the area lit in either fashion by the torch to remain unchanged. A darkness effect centered on a torch, however, will fully blanket the torch's area of primary illumination resulting in Dim lighting conditions, but will have no effect on the torch's area of secondary illumination, as that area lies wholly outside the area of the darkness spell.
This procedure is further supported by the clarification about the spell deeper darkness, which operates as darkness except in that the radius of effect is 60' and the light level is diminished by two steps (to a minimum level of Supernatural darkness; (*)this is the only place that this lighting level is mentioned or defined in the core rules).
In essence, my interpretation recognizes that the primary area of illumination contributes to the determination of the "ambient natural light" and only the secondary zone of illumination may act to increase the ambient lighting conditions with which it overlaps.
To address the OP's questions:
1) It depends on where the darkness is centered as to what exactly happens, but generally the torch (or other equipment) will shed light in its designated primary area at its designated intensity (Normal for a torch), with any area in the primary area that overlaps with the area of the darkness being diminished one step (to Dim light for a torch), while the torch will continue to increase the ambient light in its secondary area unless that secondary area is overlapped by the darkness spell in which case the torch has no effect on the ambient light in that area.
2) As the light spell is a cantrip and darkness is 2nd level, the results obtained would be identical to those for (1), unless the darkness spell was specifically used to dispel the light spell, which would end the light spell but would not cause any area of darkness to come into being.
To address the implied question of what the heck Jason Bulmahn's FAQ entry means, personally I think that he (like so many other gamers) interpreted the text at the end of darkness in the non-technical descriptive mode, rather than as a technical term. This, however, leads to unnecessary hair-splitting about what is and is not a valid source for ambient light (examples raised include "the Sun", "phosphorescent mold", and "forge-light"). I maintain that my interpretation is a legitimate one, as well as the only one that makes sense in every application.
I present it here for whatever it may be worth (probably not much).