If you think about it, dreamland is kind of like the magical world of Harry Potter. Whimsy is encouraged, and it can seem like anything is possible. So it’s no surprise that Mary GrandPré — the American Harry Potter illustrator whose jewel tones and bright swirls are synonymous with a certain boy wizard for a generation of kids — would be drawn to the real-life dream world in Jennifer Dewing’s latest children’s book, Goodnight Little Elizabeth.

The “Elizabeth” moniker is changeable to your child’s name, making each story about going off to bed a personalized keepsake. “I was hired to create all the pictures and design the book so that various names and name sizes could be incorporated throughout the book,” GrandPré explained to EW. “There has to be enough places for a long name and then a shorter name. A lot of the artwork was done on separate boards so that they could be pieced together according to the child’s name. Every book is printed and put together one at a time as a special order item. So the book you have [Elizabeth] lays out differently than a book with the name ‘Sue’ or ‘Jeff.’ [This uniqueness] is a first time experience for me.”

Read on for a Q&A where GrandPré discusses how her illustrations come together, her aesthetic and even her memories about Potter.

ENTERTAINMENT WEEKLY: Tell me about your process. Do you see a text breakdown page by page, or are you part of the process deciding how the text would be broken up?

MARY GRANDPRÉ: On this book, it was already broken up for me. I could choose to put all the type on one spread, or put it on two pages and move the type around. Basically, the process is, I got the manuscript and I really liked the story and thought it matched the kind of work that I do. So then I move on to sketches and try to come up with an overall flow for the book. I then tighten up the sketches and once I feel good about that, I send them to [the] head designer, and he shares them with his people and shares them with the author and makes sure everybody was happy with the sketches. And then it’s just a matter of going to the final painting. With a few of these [pages] I actually designed typeface.

What do you like about illustrating children’s books, specifically?

I like the fantasy world where you can bring a lot of magic into a child’s day by reading a book with them and getting them off the screen. It’s just an enjoyable way to spend some time with your child. Especially in this digital world where books aren’t doing as well as they used to, this book was really nice to do because this isn’t your average picture book that could be on a Kindle or some kind of screen. It’s more of a keepsake with the personalized pages.

There are a lot color swirls and pastels in these illustrations. I know that’s part of your general aesthetic, but it reminded me a lot of your work on Harry Potter.

Yeah, I see that too. I don’t consciously do that, I guess it just comes out! Someone was asking me about my color palate before, and I kind of recently realized that I grew up in a Catholic school and we would go to church every day and there were these stained glass windows. And that became a large part of my visual memories as a child. I think what happened was that flow and that color was such a big part of my life growing up that it’s come into my work. I’m kind of thinking that’s where it started. I can’t get rid of it! [Laughs]

In the Potter books, there is one overall color to your cover illustrations. Where do you come up with that color — discussions with publisher, J.K. Rowling, or your own interpretations of the tone of the book?

Yeah, I think it is the tone of the book. A lot of times with J.K. Rowling’s writings, she’s very descriptive and there’s a lot of visual clues throughout the book. The first three books were kind of a mix of jewel tones, and then the art director and I thought for the remaining books it might be nice to call each one out with a specific color. The fourth one was the green, fifth blue – and that was that moody time when Harry was going through puberty and it was an emotional time; almost draining. And then the sixth book was green, and I just think there was a lot of descriptions using green, ‘the green light coming from the cave’ and all of that, and the last book was that warm golden tone that kind of [symbolized] that final, triumphant color. We kind of tried to find a color that was symbolic of the story and use it on the cover.

I loved the curtains that started with the cover of the first book, like a play about to begin, and how it came full circle with the art for Deathly Hallows. Did you always have that planned?

Yes. I thought it was a good way to close the series the same way it opened. I liked that; that was fun.

I assume you didn’t talk with J.K. Rowling?

No. Well, not directly. I met her during the series while she was touring the U.S. She was always part of the approval process for the sketches, but the art director was the one who talked to her.

Were there Harry Potter fans in your life that it was hard to keep a secret from?

Oh yeah! I had to sign confidentiality agreements and not tell anyone I was working on it. I had to keep the manuscript in a safe. It was all very hush-hush; very odd. …It’s been quite a ride, that’s for sure.

Have you had a chance to see the new 15th anniversary covers?

I got a little preview of them before they came out and I think they did a really nice job. I think they just wanted to give it a new look without straying too far from what I had done. I think it was a pretty smooth transition. I’m happy with them; I think they look great.

What’s next for you?

I’m working on some paintings, works of art, things like that. Book-wise, I just finished writing a book for Scholastic, same art director and publisher that I worked on for Harry Potter, I finished writing a book and will be illustrating that for them next…. [It’s about] a young girl and her father and they’re both inventors. It’s about how they come together through their own creative discoveries. It’s actually about me and my dad.