Question 1:
Using hrimburn, my cold dmg ignites. Does "increased cold damage" increase ignite dps?

Question 2:
20/0 deadly ailments support grants 64%more ailment dmg and 10%less hit dmg. Does this mean ailments deal 64% more dmg, or 1.64*0.9 -> 47.6% more dmg?

Question 3:
Using divine ire with PTL for 100%phys->light
Using 2* call of the brotherhood for 100%light->cold
Using 2* perf nebulis with 90 max light res and cold res for 600%inc cold, 600%inc light, 80%inc elem dmg
Do I get the full 1280% increased dmg?

Question 4:
Using divine ire (50% phys->light), PTL(50%phys->light), and hrimburn(50%phys->cold)
None of my phys dmg gets converted to cold, right?

Question 5:
Using 2*call of the brotherhood (spells shock frozen enemies, 100% light->cold)
Using herald of thunder (triggers when I kill a shocked enemy)
If a lightning spell crits, does it trigger herald of thunder?

1 yes
2 64
3 yes
4 right
5 still don't know

1. Are you sure it scales the ignite itself? And it's not just scaling the hit which in turn scales the ignite. Because I'm pretty sure it doesn't scale the actual ignite. I might be mistaken tho.

5. the skill tag has 0 influence on the ailment it provides. So the wording is off in your question. Lightning damage from your spell is converted to cold 100% if using legacy cotb. Which means you deal 0 lightning damage so you are unable to shock. Unless you using 3dragons or other uniques that modify how you can apply shock.

Reference the modifier tab here.
https://pathofexile.gamepedia.com/Call_of_the_Brotherhood

Would still verify what I said with your own testing but to my knowledge this is how it works.

Btw thanks for all the d2 SnG help you've given to all.

This post was edited by Footballstar0799 on Apr 14 2019 05:24pm

my understanding is that it used to work like this, but it meant there was double dipping, so they changed it?
now you've got your hit dmg that scales off your base dmg, and your dot that also scales off your base dmg
and some modifiers work for both (like "increased damage") but some don't (spell dmg doesn't normally work for dot)

and so dot ailments now suck cuz they lost double dipping and they still can't crit (properly)?