I'm gonna use some overly simplistic numbers, just for the sake of making the math easy.
Suppose a hygrometer reads 25% when the actual RH is 50%.
Is it off by 25, or is it off by 50%?
If it's reading 35, is the actual humidity 60 or 70?
Suppose a hygrometer reads 25% when the actual RH is 50%.
Is it off by 25, or is it off by 50%?
If it's reading 35, is the actual humidity 60 or 70?