If performing a gravimetric sulfate experiment and you use ordinary filter paper instead of ashless filter paper, would results be too high or too low?

Question

If I'm trying to calculate percentage of sulfate in a sample and I used ordinary filter paper, the paper will turn to ash when ignited and be in addition to the precipitate. So wouldn't that make the % sulfate lower?

Answer 1

Isn't %SO4 = (mass BaSO4*factor/mass sample)*100
The factor converts BaSO4 to SO4. So if the mass ppt(BaSO4) + paper is higher than mass BaSO4 alone, then numerator is too large which makes %SO4 too large.