The way the rules are spread across the book for this confuses me. Here are the methods I consider with corresponding DCs when applicable:
- Read Magic spell (automatic)
- Spellcraft check DC 20 + Spell Level
- Identification spell and Spellcraft check DC 15 + Caster Level
- Identification spell and Spellcraft check DC 20 + Spell Level
- Analyze Dweomer (automatic apart from potential Will save)
At the moment, Read Magic is the one I don't doubt. Beyond that, I think these are the actual possibilities:
- Read Magic spell (automatic)
- Spellcraft DC 20+SL
- Identification spell and Spellcraft check DC 15 + Caster Level (just like any magic item)
- Analyze Dweomer (automatic apart from potential Will save)
I do not think the Spellcraft-only method is incompatible with the more general magic item identification method making use of ID spells and a Spellcraft check with a different DC. I also do not believe the Spellcraft method always requires the use of an ID spell.
But I may be wrong…
I'm curious to know whether there's a definitive answer from the RAW, and if so, what it is, or if it has to be left to subjective appreciation.
Note that I am focusing solely on identification: knowing what kind of magic is on the scroll, what it can do and, possibly, how to activate it. Since all scrolls activate the same way (Spell Completion), it's more about identifying the spells themselves. Based on the rules, I strongly believe identifying is different from using.
Here is my research so far:
When detect magic identifies a magic item's school of magic, this information refers to the school of the spell placed within the potion, scroll, or wand, or the prerequisite given for the item. (…)
Scrolls are definitely considered Magic Items and Detect Magic can identify their school of magic through their aura. It can be assumed the "identifying properties" part of Detect Magic is also possible.
Decipher the Writing: The writing on a scroll must be deciphered before a character can use it or know exactly what spell it contains. This requires a read magic spell or a successful Spellcraft check (DC 20 + spell level). (…)
This seems to say that to use or even know the content of a scroll, you need either the Read Magic spell or the given Spellcraft check with its specific DC. This is the one bit that implies scroll identification may be treated differently from all other magic items. Can one not "know exactly what spell it contains" and yet know its properties and function?
It does not say anything here about the Spellcraft check being linked to any other action such as casting Detect Magic first. This doesn't seem to be about reading an aura so much as… well, decyphering writings.
When using detect magic or identify to learn the properties of magic items, you can only attempt to ascertain the properties of an individual item once per day. Additional attempts reveal the same results.
The skill refers to these two identification spells and indicates one limitation.
Identify the properties of a magic item using detect magic: DC 15 + item's caster level
Decipher a scroll: DC 20 + spell level
There are two entries that may fit scroll identification. Both have different DC formulas. Note that the "decipher" one shows the same formula as indicated in "Decipher the Writing" and does use the word "decipher". This makes me think it is just a reference to that other section of the rules.
The only other mention of scrolls in the skill entry is for learning spells from one, so I do not think it's relevant here.
3rd Round: (…) If the items or creatures bearing the auras are in line of sight, you can make Knowledge (arcana) skill checks to determine the school of magic involved in each. (…) If the aura eminates from a magic item, you can attempt to identify its properties (see Spellcraft).
The spell refers to the skill entry for identifying properties on top of determining the school of magic. Scrolls being magic items, this should also apply to them.
Per RAW, everything seems to point at scrolls being identifiable through Detect Magic except the "Decipher the Writing" part which seems to denote an exception. I can't help but think it's a shame though, especially since I don't see any unbalance coming from using Detect Magic:
- It requires a spell
- It requires 3 rounds (for when that matters)
- You can only attempt it once per day per item (though it could be argued that the Spellcraft-only method should work the same)
- It does not allow you to read the scroll or use it
- The DC may be lower, but since it uses Caster Level it rises faster… and all the other limitations seem to compensate
Still, I may be missing some obvious abuse or other tidbits.
Best Answer
Identifying a scroll is different from deciphering a scroll and neither requires expending the scroll.
Identifying
The detect magic spell determines if there're any magic auras in the area on the first round, the number of magic auras and the most potent aura in the area on the second, and where exactly those auras are and how powerful each is on the third. With a successful Knowledge (arcana) skill check (DC 15 + spell level), the caster can determine the aura's school of magic; this check apparently takes no time and is part of the 3rd-round detect magic effect. Doing this would tell the caster only the school of the spell or spells on the scroll.
A 3-round thorough examination of the object while employing the detect magic spell permits the caster to "[i]dentify the properties of a magic item" with a successful Spellcraft check (DC 15 + scroll's caster level). This tells the caster everything about the magic item, with apparently one exception. The caster knows whether the scroll is arcane or divine, what level spell is on it, what level the spell or spells are scribed at, and so on, but identifying doesn't reveal exactly what spell is on the scroll; to do that the caster must decipher the scroll.
These 3 rounds are in addition to the first 3 rounds leading to pinpointing each aura in the area of the spell detect magic. Events happen in order unless stated to happen simultaneously.
(The analyze dweomer spell also reveals these properties, but the word dweomer is difficult to say without laughing.)
Deciphering
To find out which spell is on the scroll (and subsequently be able to activate it) the caster must decipher the scroll, which requires a successful full-round Spellcraft skill check (DC 20 + spell level), a successful 1-minute Use Magic Device skill check (DC 25 + spell level), or the read magic spell.
After the scroll's deciphered, that scroll's always deciphered for that caster. No further checks need be made, and the scroll can be employed normally.
Don't conflate identifying with deciphering. The hairs are fine and difficult to split but the game splits them anyway: When a caster identifies an item's properties, he gets command words, number of charges, and so on (pretty much just like he read the item's description from the book) but not the name of the spell on the scroll; the caster gets that and the ability to activate the scroll from deciphering the scroll.
Note: That's weird and the Pathfinder Role-playing Game buries that on page 490: "The writing on a scroll must be deciphered before a character can... know exactly what spell it contains." This also isn't exclusive to Pathfinder--both the Dungeons and Dragons 3.0 and 3.5 Dungeon Master's Guides have the exact same language in their Deciphering a Scroll sections (pages 203 and 238, respectively).
Note: A solid but dangerous case can be made for skipping the identification step if the caster already knows what he's dealing with, much in the same way someone proficient with a sword can just whack fools with the sword instead of learning its maker, properties, and history before he starts using it. The DM rolls secretly to determine if a character deciphers gibberish via the Linguistics skill, but the player rolls openly to decipher a magic scroll via the Spellcraft skill or Use Magic Device skill, so right there the player will know it's a magic scroll and, if successful in deciphering it, know the spell on it. The character can then try to activate the scroll, but--and this is really a DM's call--the character still won't know any of the scroll's properties (such as it's spell level or the scriber's caster level) because the character's not identified the scroll's properties. Just as Fighter Joe can still take swings with a magic sword without knowing its exact properties, Wizard Jim can decipher a scroll and, if he meets the requirements, cast the spell from the scroll without knowing exactly what's going to happen. I've never seen a player want to do that, but I'd totally let him. That could be hilarious.
Other Tidbits: There are spells that straight-up answer questions and get information; one could possibly use those and make a big pile of information about a scroll. There are feats and classes that are scroll-specific, and those might be useful. I've ignored both because they seem to be beyond the question's scope.