I was recently fortunate enough to find boots of fire abatement, 60% resistance. Next time I fought a fire dragon, I put them on, assuming that that 60% plus my Dark Elf 50% resistance would total complete negation of the fire damage. I was wrong.
How does resistance work in this game? Is it 50% resistance of 60%, coming to a total of 80%? What if I were to drink a 20% resistance potion? Would that bring the total to 20% of the remaining 20%, which would be 5%? (total negation in that case would be 85%)
Finally, What would happen if I were to drink a Resist Magic potion of, say, 10% on top of the previous effects? If my earlier reasoning is correct, it would be 10% of 15% added to the total.
The other possible situation here may be that only one resistance device can be active at a time. That would mean that in my encounter with the dragon, my 60% boots cancelled out my 50% racial bonus.