Wrong Type of Paint...

Yesterday Fan ask me to buy white paint to paint one of her room.Brand was correct but the type was wrong.I am not sure what it is call in English.I bought 油漆 rather then 灰水。I should be buy 灰水and not 油漆.I didn't took note of that at all.
I was sleeping when Fan called my handphone to "scold" me.I was of course speechless then.