Picture Book Illustrations
For picture books (pb) can be in color and black and white. Page length is determined by multiples of 8. The standard length is 32.
An illustrator can make room for story matter per page illustration. They may also decide to alternate. One page will consist of the story matter, and the other page will have the illustration.
A 500 words or less pb usually aims at readers in the 4-8 age group. At times, depending on the subject matter, a pb will be introduced to a higher age group of children.
In schools, if students are introduced to a new topic, many times teachers will choose a pb to explore the basics of that topic before students go on to read books at a higher level.
For ages 7-10, a picture book may contain 1,000 words or less and increase its number of pages.
A quality pb contains minimal concise wording. This allows the illustrations to carry the story visually.
Chapter Book Middle Grade Illustrations
Most Chapter and Middle Grade books use black and white illustrations. The less black ink the better. Black ink shows through the back of the illustrated page and can disturb the reading.
Color illustrations are an option in this category; however, the publisher's printing cost will go up.
My chapter book MOUSE ADVENTURES 1, ADOLFO AND ATHENA was illustrated in color. I had no issues with the ink colors showing through to the back side of the page.
The number of illustrations vary in chapter books. The older the reader, the fewer the illustrations. Older children are able to use their imagination to recreate climactic scenes in their minds.