I had several issues with this book.

The poetic rhyming was forced at a few points. The illustrations for this story, supposedly set in early medieval Ireland (with monks shown creating manuscripts similar to the Book of Kells), depict modern shoes and Roman style tonsures when the Irish during this period had their own distinct tonsure.

But the biggest problem I had with the book was the central story idea that no one had thought of using colour to illustrate the monks's writings and drawings until the protagonist accidentally stained his fingers with blackberries. Everything, we are told several times, was brown and boring until Theophane had his juicy revelation and instantly the monastery fully embraced colour in art (and interior design). That apparently happened because he was the only monk who noticed and appreciated how colourful the natural world outside their windows was. Maybe I'm wrong, but I just don't buy that premise socially or historically. Humans have used color in their art since cave paintings. So was there ever a moment in time when the monks producing these beautiful manuscripts shifted from not using colour to suddenly doing so? I doubt it, but I'm open to learning if I'm wrong.