Patrick Algermissen I've been reading these to my girls since last year, when they were 5 and 8. They can be kid-scary in places, but both of them enjoy the series very much and it hasn't been too scary for them. We've read the first 4 books, and I don't think they've been any scarier than the first two Harry Potter books. Though I have had to have conversations with them along the lines of, "If you find yourself being transported to magical lands and are worried that evil witches are going to come out of paintings and haunt you, please don't hide it from me. I will do my best to help you."
Amy rather you read it to her because it is a little bit scary, and do not use this book as a bedtime story because is going to give her bad dreams.
This answer contains spoilers… (view spoiler)[If this was a movie I would rate it PG. It is very mild as books go, but overall could be a little eerie for children. SPOILER She goes in to paintings where a boy made of paint with a sad story lives, and a black darkness comes to chase them. The main bad guy who is kind of like an ancient witch, comes in the form of a cold dark blackness creeping out of the shadows and reminds me of bits and pieces of Harry Potter's death-eaters, but you don't really see much from what I recall. There is mention of a grave in the house, and that the old families bones where kept under the house. That is the basic idea, some creepiness, but overall pretty mild otherwise. I felt the same way about my son and the Harry Potter series. He's eleven now and aloud to read/watch some of the scarier stuff. Every child is different what scares them. This one is eerie but not violent. Could make a good but mild spooky story for a child if they like that. (hide spoiler)]
Book Believer I read this book at about age ten, and I was fine. Because she is 8 maybe it'd be better if you read it to her, because it is a little bit scary.
Wolfgang Burst I read it when I was ten I and think that your daghter woud not have any problem reading this book. seeing it is way less graphic than harry potte and hunger gmaes witch i have read both of being 13 now.
David Hunt This book is a little scary but not to much. You could read it but not as a bedtime story cause it could get him scared. Its a good book and not really scary