Illustrators please note
The working image size is 187mm x 250mm. This fits on an A4 page with some white margins.
Working by hand:
Use black ink on smooth white A4 card, at least 150 gsm (not 80 gsm photocopy paper).
Erase pencil lines.
Your scan should be at least 300 dpi.
Working on a computer:
If creating using Photoshop or similar software, create a 300dpi file sized 187mm x 250mm. This shrinks to the image area of the book.
If you test print your work, you can check that it is as legible and visual as it is on your computer screen. Print it at 74%, which is the image area of the book.
Your work should not be too wordy, and the text should be big enough to be easily read.
Summary:
Use black on white.
Use portrait orientation (not landscape).
Your digital file should be 187mm x 250mm or larger, supplied as a PDF.