The spell Disguise Self is described as giving a +10 bonus on Disguise checks, and under the description for the Disguise skill, it suggests a similar bonus for the spell Alter Self.
Is that the extent of it, or does it also eliminate the Disguise check penalties for different race, gender, age category, and/or size?
Smeelbo
It doesn't eliminate the penalties. You are still a man pretending to be a woman, an elf pretending to be a dwarf, etc. The +10 bonus makes is a lot easier to overcome those penalties.
Alter self is a spell of the Polymorph subschool, and so grants you a +20 to Disguise.
RAW, I believe all the normal penalties still apply. Although polymorph changes your physical appearance to match the new type of creature, the further from your own form you've gone the easier it is for someone to tell that you're "not in your own skin", so to speak.
I believe it also allows you to create a disguise as a standard action.
Action: Creating a disguise requires 1d3 × 10 minutes of work. Using magic (such as the disguise self spell) reduces this action to the time required to cast the spell or trigger the effect.
But yes, +10 to the skill check is the primary benefit. There's no elimination of penalties.
Yep. From PFRD
Disguise Check Modifier
Minor details only +5
Disguised as different gender1 –2
Disguised as different race1 –2
Disguised as different age category1 –22
Disguised as different size category1 –10
1 These modifiers are cumulative; use all that apply.
2 Per step of difference between your actual age category and your disguised age category. The steps are: young (younger than adulthood), adulthood, middle age, old, and venerable.
Disguise Self gives a +10 bonus on Disguise check.
Alter Self would get rid of the size penalty.
So assume Mr Guard is looking for a gnome female and your halforc male trys to get past the DC would be 10(passive checking from guard)+2(different gender)+2(different race)+10(size).
DC for disguise to work would be 24
Apply Disguise Self spell and the DC drops to 14. So in effect Disguise Self spell doeseliminate the penalty.
Alter Self changes your size (and adds STR/DEX and other stuff) so all that would do is "eliminate" the size difference.
So Mr halforc with Disguise Self and Alter Self running the DC for being a gnome female would be 24-10(Disguise Self)-10(Alter Self) or DC4
Yep. From PFRD
Disguise Check Modifier
Minor details only +5
Disguised as different gender1 –2
Disguised as different race1 –2
Disguised as different age category1 –22
Disguised as different size category1 –10
1 These modifiers are cumulative; use all that apply.
2 Per step of difference between your actual age category and your disguised age category. The steps are: young (younger than adulthood), adulthood, middle age, old, and venerable.Disguise Self gives a +10 bonus on Disguise check.
Alter Self would get rid of the size penalty.So assume Mr Guard is looking for a gnome female and your halforc male trys to get past the DC would be 10(passive checking from guard)+2(different gender)+2(different race)+10(size).
DC for disguise to work would be 24
Apply Disguise Self spell and the DC drops to 14. So in effect Disguise Self spell doeseliminate the penalty.Alter Self changes your size (and adds STR/DEX and other stuff) so all that would do is "eliminate" the size difference.
So Mr halforc with Disguise Self and Alter Self running the DC for being a gnome female would be 24-10(Disguise Self)-10(Alter Self) or DC4
your doing that wrong, disguise is opposed by perception.
you gnome would roll d20 + 10 (disguise self) + 10 (alter self) - 2 (gender) - 2 (race) + # (Charisma bonus) + # (ranks in disguise) + 3 (if disguise is class skill)
also the disguise check is done secretly, which as we all know the DM/GM does the roll for you.